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Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya 5.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]11<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]12
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]13<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +0000[diff] [blame]16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]19
20<p>Libxml is the XML C library developped for the Gnome project. XML itself
21is a metalanguage to design markup languages, i.e. text language where
22semantic and structure are added to the content using extra "markup"
23information enclosed between angle bracket. HTML is the most well-known
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]24markup language. Though the library is written in C <a href="python.html">a
25variety of language binding</a> makes it available in other environments.</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]26
27<p>Libxml2 implements a number of existing standards related to markup
28languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]29<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]30 <li>the XML standard: <a
31 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
32 <li>Namespaces in XML: <a
33 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
34 <li>XML Base: <a
35 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]36 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
37 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]38 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
39 <li>XML Path Language (XPath) 1.0: <a
40 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
41 <li>HTML4 parser: <a
42 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
43 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
44 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
45 <li>XML Inclusions (XInclude) Version 1.0: <a
46 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
47 <li>[ISO-8859-1], <a
48 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
49 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
50 [UTF-16] core encodings</li>
51 <li>part of SGML Open Technical Resolution TR9401:1997</li>
52 <li>XML Catalogs Working Draft 06 August 2001: <a
53 href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
Daniel Veillard5c396542002-03-15 07:57:50 +0000[diff] [blame]54 <li>Canonical XML Version 1.0: <a
55 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]56 and the Exclusive XML Canonicalization CR draft <a
57 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]58</ul>
59
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]60<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +0000[diff] [blame]61strict way. As of release 2.4.16, libxml2 passes all 1800+ tests from the <a
62href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
63Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +0000[diff] [blame]64
65<p>To some extent libxml2 provide some support for the following other
66specification but don't claim to implement them:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]67<ul>
68 <li>Document Object Model (DOM) <a
69 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
70 it doesn't implement the API itself, gdome2 does this in top of
71 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]72 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
73 libxml implements a basic FTP client code</li>
74 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
75 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]76 <li>SAX: a minimal SAX implementation compatible with early expat
77 versions</li>
78 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
79 XML</li>
80</ul>
81
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]82<p>Libxml2 is known to be very portable, the library should build and work
83without serious troubles on a variety of systems (Linux, Unix, Windows,
84CygWin, MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]85
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]86<p>Separate documents:</p>
87<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]88 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]89 implementation of XSLT 1.0 and common extensions like EXSLT for
90 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]91 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]92 : a standard DOM2 implementation for libxml2</li>
93 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
94 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
95 Digital Signature</a> for libxml2</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]96</ul>
97
98<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]99
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]100<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]101href="http://www.w3.org/XML/">XML</a> C library developped for the <a
102href="http://www.gnome.org/">Gnome</a> project. <a
103href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
104structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]105
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]106<p>Here are some key points about libxml:</p>
107<ul>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]108 <li>Libxml exports Push (progressive) and Pull (blocking) type parser
109 interfaces for both XML and HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]110 <li>Libxml can do DTD validation at parse time, using a parsed document
111 instance, or with an arbitrary DTD.</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]112 <li>Libxml includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000[diff] [blame]113 href="http://www.w3.org/TR/xpath">XPath</a>, <a
114 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
115 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]116 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]117 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]118 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]119 <li>Basic support for HTTP and FTP client allowing aplications to fetch
120 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]121 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]122 <li>The internal document repesentation is as close as possible to the <a
123 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
124 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]125 like interface</a>; the interface is designed to be compatible with <a
126 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]127 <li>This library is released under the <a
128 href="http://www.opensource.org/licenses/mit-license.html">MIT
129 Licence</a> see the Copyright file in the distribution for the precise
130 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]131</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]132
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]133<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]134Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]135style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
136libxml2</p>
137
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]138<h2><a name="FAQ">FAQ</a></h2>
139
140<p>Table of Content:</p>
141<ul>
142 <li><a href="FAQ.html#Licence">Licence(s)</a></li>
143 <li><a href="FAQ.html#Installati">Installation</a></li>
144 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
145 <li><a href="FAQ.html#Developer">Developer corner</a></li>
146</ul>
147
148<h3><a name="Licence">Licence</a>(s)</h3>
149<ol>
150 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]151 <p>libxml is released under the <a
152 href="http://www.opensource.org/licenses/mit-license.html">MIT
153 Licence</a>, see the file Copyright in the distribution for the precise
154 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]155 </li>
156 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]157 <p>Yes. The MIT Licence allows you to also keep proprietary the changes
158 you made to libxml, but it would be graceful to provide back bugfixes and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]159 improvements as patches for possible incorporation in the main
160 development tree</p>
161 </li>
162</ol>
163
164<h3><a name="Installati">Installation</a></h3>
165<ol>
166 <li>Unless you are forced to because your application links with a Gnome
167 library requiring it, <strong><span style="background-color: #FF0000">Do
168 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]169 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]170 <p>The original distribution comes from <a
171 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
172 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
173 <p>Most linux and Bsd distribution includes libxml, this is probably the
174 safer way for end-users</p>
175 <p>David Doolin provides precompiled Windows versions at <a
176 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
177 </li>
178 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
179 <ul>
180 <li>If you are not concerned by any existing backward compatibility
181 with existing application, install libxml2 only</li>
182 <li>If you are not doing development, you can safely install both.
183 usually the packages <a
184 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
185 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
186 compatible (this is not the case for development packages)</li>
187 <li>If you are a developer and your system provides separate packaging
188 for shared libraries and the development components, it is possible
189 to install libxml and libxml2, and also <a
190 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
191 and <a
192 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
193 too for libxml2 &gt;= 2.3.0</li>
194 <li>If you are developing a new application, please develop against
195 libxml2(-devel)</li>
196 </ul>
197 </li>
198 <li><em>I can't install the libxml package it conflicts with libxml0</em>
199 <p>You probably have an old libxml0 package used to provide the shared
200 library for libxml.so.0, you can probably safely remove it. Anyway the
201 libxml packages provided on <a
202 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
203 libxml.so.0</p>
204 </li>
205 <li><em>I can't install the libxml(2) RPM package due to failed
206 dependancies</em>
207 <p>The most generic solution is to refetch the latest src.rpm , and
208 rebuild it locally with</p>
209 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
210 <p>if everything goes well it will generate two binary rpm (one providing
211 the shared libs and xmllint, and the other one, the -devel package
212 providing includes, static libraries and scripts needed to build
213 applications with libxml(2)) that you can install locally.</p>
214 </li>
215</ol>
216
217<h3><a name="Compilatio">Compilation</a></h3>
218<ol>
219 <li><em>What is the process to compile libxml ?</em>
220 <p>As most UNIX libraries libxml follows the "standard":</p>
221 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
222 <p><code>cd libxml-xxxx</code></p>
223 <p><code>./configure --help</code></p>
224 <p>to see the options, then the compilation/installation proper</p>
225 <p><code>./configure [possible options]</code></p>
226 <p><code>make</code></p>
227 <p><code>make install</code></p>
228 <p>At that point you may have to rerun ldconfig or similar utility to
229 update your list of installed shared libs.</p>
230 </li>
231 <li><em>What other libraries are needed to compile/install libxml ?</em>
232 <p>Libxml does not requires any other library, the normal C ANSI API
233 should be sufficient (please report any violation to this rule you may
234 find).</p>
235 <p>However if found at configuration time libxml will detect and use the
236 following libs:</p>
237 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]238 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
239 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]240 <li>iconv: a powerful character encoding conversion library. It's
241 included by default on recent glibc libraries, so it doesn't need to
242 be installed specifically on linux. It seems it's now <a
243 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
244 of the official UNIX</a> specification. Here is one <a
245 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
246 of the library</a> which source can be found <a
247 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
248 </ul>
249 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]250 <li><em>make check fails on some platforms</em>
251 <p>Sometime the regression tests results don't completely match the value
252 produced by the parser, and the makefile uses diff to print the delta. On
253 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000[diff] [blame]254 diff is small this is probably not a serious problem.</p>
255 <p>Sometimes (especially on Solaris) make checks fails due to limitations
256 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]257 </li>
258 <li><em>I use the CVS version and there is no configure script</em>
259 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
260 script to regenerate the configure and Makefiles, like:</p>
261 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
262 </li>
263 <li><em>I have troubles when running make tests with gcc-3.0</em>
264 <p>It seems the initial release of gcc-3.0 has a problem with the
265 optimizer which miscompiles the URI module. Please use another
266 compiler</p>
267 </li>
268</ol>
269
270<h3><a name="Developer">Developer</a> corner</h3>
271<ol>
272 <li><em>xmlDocDump() generates output on one line</em>
273 <p>libxml will not <strong>invent</strong> spaces in the content of a
274 document since <strong>all spaces in the content of a document are
275 significant</strong>. If you build a tree from the API and want
276 indentation:</p>
277 <ol>
278 <li>the correct way is to generate those yourself too</li>
279 <li>the dangerous way is to ask libxml to add those blanks to your
280 content <strong>modifying the content of your document in the
281 process</strong>. The result may not be what you expect. There is
282 <strong>NO</strong> way to guarantee that such a modification won't
283 impact other part of the content of your document. See <a
284 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
285 ()</a> and <a
286 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
287 ()</a></li>
288 </ol>
289 </li>
290 <li>Extra nodes in the document:
291 <p><em>For a XML file as below:</em></p>
292 <pre>&lt;?xml version="1.0"?&gt;
293&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
294&lt;NODE CommFlag="0"/&gt;
295&lt;NODE CommFlag="1"/&gt;
296&lt;/PLAN&gt;</pre>
297 <p><em>after parsing it with the function
298 pxmlDoc=xmlParseFile(...);</em></p>
299 <p><em>I want to the get the content of the first node (node with the
300 CommFlag="0")</em></p>
301 <p><em>so I did it as following;</em></p>
302 <pre>xmlNodePtr pode;
303pnode=pxmlDoc-&gt;children-&gt;children;</pre>
304 <p><em>but it does not work. If I change it to</em></p>
305 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
306 <p><em>then it works. Can someone explain it to me.</em></p>
307 <p></p>
308 <p>In XML all characters in the content of the document are significant
309 <strong>including blanks and formatting line breaks</strong>.</p>
310 <p>The extra nodes you are wondering about are just that, text nodes with
311 the formatting spaces wich are part of the document but that people tend
312 to forget. There is a function <a
313 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
314 ()</a> to remove those at parse time, but that's an heuristic, and its
315 use should be limited to case where you are sure there is no
316 mixed-content in the document.</p>
317 </li>
318 <li><em>I get compilation errors of existing code like when accessing
319 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
320 <p>You are compiling code developed for libxml version 1 and using a
321 libxml2 development environment. Either switch back to libxml v1 devel or
322 even better fix the code to compile with libxml2 (or both) by <a
323 href="upgrade.html">following the instructions</a>.</p>
324 </li>
325 <li><em>I get compilation errors about non existing
326 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
327 fields</em>
328 <p>The source code you are using has been <a
329 href="upgrade.html">upgraded</a> to be able to compile with both libxml
330 and libxml2, but you need to install a more recent version:
331 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
332 </li>
333 <li><em>XPath implementation looks seriously broken</em>
334 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]335 a recent version, there is no known bug in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]336 </li>
337 <li><em>The example provided in the web page does not compile</em>
338 <p>It's hard to maintain the documentation in sync with the code
339 &lt;grin/&gt; ...</p>
340 <p>Check the previous points 1/ and 2/ raised before, and send
341 patches.</p>
342 </li>
343 <li><em>Where can I get more examples and informations than in the web
344 page</em>
345 <p>Ideally a libxml book would be nice. I have no such plan ... But you
346 can:</p>
347 <ul>
348 <li>check more deeply the <a href="html/libxml-lib.html">existing
349 generated doc</a></li>
350 <li>looks for examples of use for libxml function using the Gnome code
351 for example the following will query the full Gnome CVs base for the
352 use of the <strong>xmlAddChild()</strong> function:
353 <p><a
354 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
355 <p>This may be slow, a large hardware donation to the gnome project
356 could cure this :-)</p>
357 </li>
358 <li><a
359 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]360 the libxml source</a> , I try to write code as clean and documented
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]361 as possible, so looking at it may be helpful. Especially the code of
362 xmllint.c and of the various testXXX.c tests programs should provide
363 good example on how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]364 </ul>
365 </li>
366 <li>What about C++ ?
367 <p>libxml is written in pure C in order to allow easy reuse on a number
368 of platforms, including embedded systems. I don't intend to convert to
369 C++.</p>
370 <p>There is however a C++ wrapper provided by Ari Johnson
371 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
372 <p>Website: <a
373 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
374 <p>Download: <a
375 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
376 </li>
377 <li>How to validate a document a posteriori ?
378 <p>It is possible to validate documents which had not been validated at
379 initial parsing time or documents who have been built from scratch using
380 the API. Use the <a
381 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
382 function. It is also possible to simply add a Dtd to an existing
383 document:</p>
384 <pre>xmlDocPtr doc; /* your existing document */
385 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
386 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
387
388 doc-&gt;intSubset = dtd;
389 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
390 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
391 </pre>
392 </li>
393 <li>etc ...</li>
394</ol>
395
396<p></p>
397
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]398<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]399
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]400<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]401<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]402 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]403 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]404 documentation</a> automatically extracted from code comments (using <a
405 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
406 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]407 <li>Look at the documentation about <a href="encoding.html">libxml
408 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000[diff] [blame]409 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]410 examples</a> on how to use libxml.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]411 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]412 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
413 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]414 <li>George Lebl wrote <a
415 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]416 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]417 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
418 file</a></li>
419 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
420 starting a new project using libxml you should really use the 2.x
421 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000[diff] [blame]422 <li>And don't forget to look at the <a
423 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]424</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]425
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]426<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]427
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]428<p>Well, bugs or missing features are always possible, and I will make a
429point of fixing them in a timely fashion. The best way to report a bug is to
430use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
431bug tracking database</a> (make sure to use the "libxml" module name). I look
432at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]433still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]434
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]435<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]436href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
437href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]438href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
439please visit the <a
440href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
441follow the instructions. <strong>Do not send code, I won't debug it</strong>
442(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]443
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]444<p>Check the following <strong><span style="color: #FF0000">before
445posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]446<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]447 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]448 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
449 version</a>, and that the problem still shows up in those</li>
450 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
451 archives</a> to see if the problem was reported already, in this case
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]452 there is probably a fix available, similary check the <a
453 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]454 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]455 <li>make sure you can reproduce the bug with xmllint or one of the test
456 programs found in source in the distribution</li>
457 <li>Please send the command showing the error as well as the input (as an
458 attachement)</li>
459</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]460
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]461<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]462href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]463related I will approve it.. Please do not send me mail directly, it makes
464things really harder to track and in some cases I'm not the best person to
465answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]466
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]467<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]468probably be processed faster.</p>
469
470<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]471href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]472provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]473questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]474documentantion</a> is not as polished as I would like (i need to learn more
475about Docbook), but it's a good starting point.</p>
476
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]477<h2><a name="help">How to help</a></h2>
478
479<p>You can help the project in various ways, the best thing to do first is to
480subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]481href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
482href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]483database:</a>:</p>
484<ol>
485 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]486 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]487 be integrated in all cases but help pinpointing portability problems
488 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]489 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]490 as HTML diffs).</li>
491 <li>provide new documentations pieces (translations, examples, etc ...)</li>
492 <li>Check the TODO file and try to close one of the items</li>
493 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]494 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
495 </a>before to avoid synchronization problems and check that the suggested
496 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]497</ol>
498
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]499<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]500
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]501<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]502href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
503href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
504href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]505href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]506as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]507archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]508href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]509packages</a>, Antonin Sprinzl also provide <a
510href="ftp://gd.tuwien.ac.at/pub/libxml/">a mirror in Austria</a>. (NOTE that
511you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]512href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
513href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]514packages installed to compile applications using libxml.) <a
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]515href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
516maintainer of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]517href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]518provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]519Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
520binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]521
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]522<p><a name="Snapshot">Snapshot:</a></p>
523<ul>
524 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]525 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]526 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]527 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]528</ul>
529
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]530<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]531
532<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]533platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]534languages have been provided, and can be found in the <a
535href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]536
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]537<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]538<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]539 <li><p>The <a
540 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]541 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]542 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
543 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]544 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]545 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]546</ul>
547
548<h2><a name="News">News</a></h2>
549
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]550<h3>CVS only : check the <a
551href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]552for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]553
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]554<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]555you want to test those</p>
556<ul>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]557 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
558 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]559</ul>
560
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]561<h3>2.4.20: Apr 15 2002</h3>
562<ul>
563 <li>bug fixes: file descriptor leak, XPath, HTML ouput, DTD validation</li>
564 <li>XPath conformance testing by Richard Jinks</li>
565 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
566 libxml.m4</li>
567</ul>
568
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]569<h3>2.4.19: Mar 25 2002</h3>
570<ul>
571 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
572 encoder</li>
573 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]574 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]575 <li>revamp of the Windows build and Makefiles</li>
576</ul>
577
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]578<h3>2.4.18: Mar 18 2002</h3>
579<ul>
580 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
581 xpath</li>
582 <li>removed the --with-buffer option it was becoming unmaintainable</li>
583 <li>serious cleanup of the Python makefiles</li>
584 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
585 <li>Fixes for Windows build, cleanup of the documentation</li>
586</ul>
587
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]588<h3>2.4.17: Mar 8 2002</h3>
589<ul>
590 <li>a lot of bug fixes, including "namespace nodes have no parents in
591 XPath"</li>
592 <li>fixed/improved the Python wrappers, added more examples and more
593 regression tests, XPath extension functions can now return node-sets</li>
594 <li>added the XML Canonalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]595</ul>
596
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]597<h3>2.4.16: Feb 20 2002</h3>
598<ul>
599 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
600 from OASIS and W3C. Compliance has been significantly improved.</li>
601 <li>a couple of portability fixes too.</li>
602</ul>
603
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]604<h3>2.4.15: Feb 11 2002</h3>
605<ul>
606 <li>Fixed the Makefiles, especially the python module ones</li>
607 <li>A few bug fixes and cleanup</li>
608 <li>Includes cleanup</li>
609</ul>
610
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]611<h3>2.4.14: Feb 8 2002</h3>
612<ul>
613 <li>Change of Licence to the <a
614 href="http://www.opensource.org/licenses/mit-license.html">MIT
615 Licence</a> basisally for integration in XFree86 codebase, and removing
616 confusion around the previous dual-licencing</li>
617 <li>added Python bindings, beta software but should already be quite
618 complete</li>
619 <li>a large number of fixes and cleanups, especially for all tree
620 manipulations</li>
621 <li>cleanup of the headers, generation of a reference API definition in
622 XML</li>
623</ul>
624
625<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]626<ul>
627 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
628 <li>cleanup of timing code from Justin Fletcher</li>
629 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
630 Narojnyi</li>
631 <li>Cygwin patch from Robert Collins</li>
632 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
633</ul>
634
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]635<h3>2.4.12: Dec 7 2001</h3>
636<ul>
637 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
638 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
639 (robert)</li>
640 <li>Eric Lavigne contributed project files for MacOS</li>
641 <li>some makefiles cleanups</li>
642</ul>
643
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]644<h3>2.4.11: Nov 26 2001</h3>
645<ul>
646 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
647 cleanups</li>
648 <li>xmllint man pages improvement by Heiko Rupp</li>
649 <li>updated VMS build instructions from John A Fotheringham</li>
650 <li>Windows Makefiles updates from Igor</li>
651</ul>
652
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]653<h3>2.4.10: Nov 10 2001</h3>
654<ul>
655 <li>URI escaping fix (Joel Young)</li>
656 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
657 <li>Fixes namespace handling problems when using DTD and validation</li>
658 <li>improvements on xmllint: Morus Walter patches for --format and
659 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
660 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
661 <li>fixes to the HTML parser</li>
662</ul>
663
664<h3>2.4.9: Nov 6 2001</h3>
665<ul>
666 <li>fixes more catalog bugs</li>
667 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
668</ul>
669
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]670<h3>2.4.8: Nov 4 2001</h3>
671<ul>
672 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
673 tool</li>
674 <li>fixed a compile errors and some includes troubles.</li>
675</ul>
676
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]677<h3>2.4.7: Oct 30 2001</h3>
678<ul>
679 <li>exported some debugging interfaces</li>
680 <li>serious rewrite of the catalog code</li>
681 <li>integrated Gary Pennington thread safety patch, added configure option
682 and regression tests</li>
683 <li>removed an HTML parser bug</li>
684 <li>fixed a couple of potentially serious validation bugs</li>
685 <li>integrated the SGML DocBook support in xmllint</li>
686 <li>changed the nanoftp anonymous login passwd</li>
687 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
688 <li>general bug fixes</li>
689 <li>updated xmllint man page by John Fleck</li>
690 <li>some VMS and Windows updates</li>
691</ul>
692
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]693<h3>2.4.6: Oct 10 2001</h3>
694<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]695 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]696 <li>portability and configure fixes</li>
697 <li>an infinite loop on the HTML parser was removed (William)</li>
698 <li>Windows makefile patches from Igor</li>
699 <li>fixed half a dozen bugs reported fof libxml or libxslt</li>
700 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
701</ul>
702
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]703<h3>2.4.5: Sep 14 2001</h3>
704<ul>
705 <li>Remove a few annoying bugs in 2.4.4</li>
706 <li>forces the HTML serializer to output decimal charrefs since some
707 version of Netscape can't handle hexadecimal ones</li>
708</ul>
709
710<h3>1.8.16: Sep 14 2001</h3>
711<ul>
712 <li>maintenance release of the old libxml1 branch, couple of bug and
713 portability fixes</li>
714</ul>
715
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]716<h3>2.4.4: Sep 12 2001</h3>
717<ul>
718 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
719 Catalog</li>
720 <li>a few bug fixes and some portability changes</li>
721 <li>some documentation cleanups</li>
722</ul>
723
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]724<h3>2.4.3: Aug 23 2001</h3>
725<ul>
726 <li>XML Catalog support see the doc</li>
727 <li>New NaN/Infinity floating point code</li>
728 <li>A few bug fixes</li>
729</ul>
730
731<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]732<ul>
733 <li>adds xmlLineNumbersDefault() to control line number generation</li>
734 <li>lot of bug fixes</li>
735 <li>the Microsoft MSC projects files shuld now be up to date</li>
736 <li>inheritance of namespaces from DTD defaulted attributes</li>
737 <li>fixes a serious potential security bug</li>
738 <li>added a --format option to xmllint</li>
739</ul>
740
741<h3>2.4.1: July 24 2001</h3>
742<ul>
743 <li>possibility to keep line numbers in the tree</li>
744 <li>some computation NaN fixes</li>
745 <li>extension of the XPath API</li>
746 <li>cleanup for alpha and ia64 targets</li>
747 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]748</ul>
749
750<h3>2.4.0: July 10 2001</h3>
751<ul>
752 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
753 <li>Fixed XML Base implementation, added a coupel of examples to the
754 regression tests</li>
755 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]756</ul>
757
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]758<h3>2.3.14: July 5 2001</h3>
759<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]760 <li>fixed some entities problems and reduce mem requirement when
761 substituing them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]762 <li>lots of improvements in the XPath queries interpreter can be
763 substancially faster</li>
764 <li>Makefiles and configure cleanups</li>
765 <li>Fixes to XPath variable eval, and compare on empty node set</li>
766 <li>HTML tag closing bug fixed</li>
767 <li>Fixed an URI reference computating problem when validating</li>
768</ul>
769
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]770<h3>2.3.13: June 28 2001</h3>
771<ul>
772 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
773 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
774</ul>
775
776<h3>1.8.14: June 28 2001</h3>
777<ul>
778 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
779 <li>Small Makefile fix</li>
780</ul>
781
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]782<h3>2.3.12: June 26 2001</h3>
783<ul>
784 <li>lots of cleanup</li>
785 <li>a couple of validation fix</li>
786 <li>fixed line number counting</li>
787 <li>fixed serious problems in the XInclude processing</li>
788 <li>added support for UTF8 BOM at beginning of entities</li>
789 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
790 miscompile uri.c (William), Thomas Leitner provided a fix for the
791 optimizer on Tru64</li>
792 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
793 compilation on Windows MSC</li>
794 <li>update of libxml-doc.el (Felix Natter)</li>
795 <li>fixed 2 bugs in URI normalization code</li>
796</ul>
797
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]798<h3>2.3.11: June 17 2001</h3>
799<ul>
800 <li>updates to trio, Makefiles and configure should fix some portability
801 problems (alpha)</li>
802 <li>fixed some HTML serialization problems (pre, script, and block/inline
803 handling), added encoding aware APIs, cleanup of this code</li>
804 <li>added xmlHasNsProp()</li>
805 <li>implemented a specific PI for encoding support in the DocBook SGML
806 parser</li>
807 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
808 node selection)</li>
809 <li>fixed a performance problem and an error in the validation code</li>
810 <li>fixed XInclude routine to implement the recursive behaviour</li>
811 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
812 <li>added --version to xmllint for bug reports</li>
813</ul>
814
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]815<h3>2.3.10: June 1 2001</h3>
816<ul>
817 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]818 <li>a number of reported bugs got fixed, in XPath, iconv detection,
819 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]820 <li>XPath string function should now handle unicode correctly</li>
821</ul>
822
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]823<h3>2.3.9: May 19 2001</h3>
824
825<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
826<ul>
827 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
828 <li>some serious speed optimisation again</li>
829 <li>some documentation cleanups</li>
830 <li>trying to get better linking on solaris (-R)</li>
831 <li>XPath API cleanup from Thomas Broyer</li>
832 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
833 xmlValidGetValidElements()</li>
834 <li>Added an INSTALL file</li>
835 <li>Attribute removal added to API: #54433</li>
836 <li>added a basic support for SGML catalogs</li>
837 <li>fixed xmlKeepBlanksDefault(0) API</li>
838 <li>bugfix in xmlNodeGetLang()</li>
839 <li>fixed a small configure portability problem</li>
840 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
841</ul>
842
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]843<h3>1.8.13: May 14 2001</h3>
844<ul>
845 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
846</ul>
847
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]848<h3>2.3.8: May 3 2001</h3>
849<ul>
850 <li>Integrated an SGML DocBook parser for the Gnome project</li>
851 <li>Fixed a few things in the HTML parser</li>
852 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
853 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]854 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
855 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]856 <li>incorporated more Windows cleanup</li>
857 <li>added xmlSaveFormatFile()</li>
858 <li>fixed problems in copying nodes with entities references (gdome)</li>
859 <li>removed some troubles surrounding the new validation module</li>
860</ul>
861
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]862<h3>2.3.7: April 22 2001</h3>
863<ul>
864 <li>lots of small bug fixes, corrected XPointer</li>
865 <li>Non determinist content model validation support</li>
866 <li>added xmlDocCopyNode for gdome2</li>
867 <li>revamped the way the HTML parser handles end of tags</li>
868 <li>XPath: corrctions of namespacessupport and number formatting</li>
869 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
870 <li>HTML ouput fixes from P C Chow and William M. Brack</li>
871 <li>Improved validation speed sensible for DocBook</li>
872 <li>fixed a big bug with ID declared in external parsed entities</li>
873 <li>portability fixes, update of Trio from Bjorn Reese</li>
874</ul>
875
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]876<h3>2.3.6: April 8 2001</h3>
877<ul>
878 <li>Code cleanup using extreme gcc compiler warning options, found and
879 cleared half a dozen potential problem</li>
880 <li>the Eazel team found an XML parser bug</li>
881 <li>cleaned up the user of some of the string formatting function. used the
882 trio library code to provide the one needed when the platform is missing
883 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]884 <li>xpath: removed a memory leak and fixed the predicate evaluation
885 problem, extended the testsuite and cleaned up the result. XPointer seems
886 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]887</ul>
888
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]889<h3>2.3.5: Mar 23 2001</h3>
890<ul>
891 <li>Biggest change is separate parsing and evaluation of XPath expressions,
892 there is some new APIs for this too</li>
893 <li>included a number of bug fixes(XML push parser, 51876, notations,
894 52299)</li>
895 <li>Fixed some portability issues</li>
896</ul>
897
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]898<h3>2.3.4: Mar 10 2001</h3>
899<ul>
900 <li>Fixed bugs #51860 and #51861</li>
901 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
902 size to be application tunable.</li>
903 <li>Some cleanup in the validation code, still a bug left and this part
904 should probably be rewritten to support ambiguous content model :-\</li>
905 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
906 parser</li>
907 <li>Fixed another bug in xmlNodeGetContent()</li>
908 <li>Bjorn fixed XPath node collection and Number formatting</li>
909 <li>Fixed a loop reported in the HTML parsing</li>
910 <li>blank space are reported even if the Dtd content model proves that they
911 are formatting spaces, this is for XmL conformance</li>
912</ul>
913
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]914<h3>2.3.3: Mar 1 2001</h3>
915<ul>
916 <li>small change in XPath for XSLT</li>
917 <li>documentation cleanups</li>
918 <li>fix in validation by Gary Pennington</li>
919 <li>serious parsing performances improvements</li>
920</ul>
921
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]922<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]923<ul>
924 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
925 <li>fixed a Dtd parsing bug</li>
926 <li>fixed a bug in xmlNodeGetContent</li>
927 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
928</ul>
929
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]930<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]931<ul>
932 <li>some XPath and HTML bug fixes for XSLT</li>
933 <li>small extension of the hash table interfaces for DOM gdome2
934 implementation</li>
935 <li>A few bug fixes</li>
936</ul>
937
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]938<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]939<ul>
940 <li>Lots of XPath bug fixes</li>
941 <li>Add a mode with Dtd lookup but without validation error reporting for
942 XSLT</li>
943 <li>Add support for text node without escaping (XSLT)</li>
944 <li>bug fixes for xmlCheckFilename</li>
945 <li>validation code bug fixes from Gary Pennington</li>
946 <li>Patch from Paul D. Smith correcting URI path normalization</li>
947 <li>Patch to allow simultaneous install of libxml-devel and
948 libxml2-devel</li>
949 <li>the example Makefile is now fixed</li>
950 <li>added HTML to the RPM packages</li>
951 <li>tree copying bugfixes</li>
952 <li>updates to Windows makefiles</li>
953 <li>optimisation patch from Bjorn Reese</li>
954</ul>
955
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]956<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]957<ul>
958 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
959 <li>added htmlHandleOmittedElem()</li>
960 <li>Applied Bjorn Reese's IPV6 first patch</li>
961 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]962 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]963</ul>
964
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]965<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]966<ul>
967 <li>Fix the Windows problems of 2.2.8</li>
968 <li>integrate OpenVMS patches</li>
969 <li>better handling of some nasty HTML input</li>
970 <li>Improved the XPointer implementation</li>
971 <li>integrate a number of provided patches</li>
972</ul>
973
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]974<h3>2.2.9: Nov 25 2000</h3>
975<ul>
976 <li>erroneous release :-(</li>
977</ul>
978
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]979<h3>2.2.8: Nov 13 2000</h3>
980<ul>
981 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
982 support</li>
983 <li>Patch in conditional section handling</li>
984 <li>updated MS compiler project</li>
985 <li>fixed some XPath problems</li>
986 <li>added an URI escaping function</li>
987 <li>some other bug fixes</li>
988</ul>
989
990<h3>2.2.7: Oct 31 2000</h3>
991<ul>
992 <li>added message redirection</li>
993 <li>XPath improvements (thanks TOM !)</li>
994 <li>xmlIOParseDTD() added</li>
995 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
996 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
997</ul>
998
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]999<h3>2.2.6: Oct 25 2000:</h3>
1000<ul>
1001 <li>Added an hash table module, migrated a number of internal structure to
1002 those</li>
1003 <li>Fixed a posteriori validation problems</li>
1004 <li>HTTP module cleanups</li>
1005 <li>HTML parser improvements (tag errors, script/style handling, attribute
1006 normalization)</li>
1007 <li>coalescing of adjacent text nodes</li>
1008 <li>couple of XPath bug fixes, exported the internal API</li>
1009</ul>
1010
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1011<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1012<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1013 <li>XPointer implementation and testsuite</li>
1014 <li>Lot of XPath fixes, added variable and functions registration, more
1015 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1016 <li>Portability fixes, lots of enhancements toward an easy Windows build
1017 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1018 <li>Late validation fixes</li>
1019 <li>Integrated a lot of contributed patches</li>
1020 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1021 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1022</ul>
1023
1024<h3>2.2.4: Oct 1 2000:</h3>
1025<ul>
1026 <li>main XPath problem fixed</li>
1027 <li>Integrated portability patches for Windows</li>
1028 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1029</ul>
1030
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1031<h3>2.2.3: Sep 17 2000</h3>
1032<ul>
1033 <li>bug fixes</li>
1034 <li>cleanup of entity handling code</li>
1035 <li>overall review of all loops in the parsers, all sprintf usage has been
1036 checked too</li>
1037 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
1038 works smoothly now.</li>
1039</ul>
1040
1041<h3>1.8.10: Sep 6 2000</h3>
1042<ul>
1043 <li>bug fix release for some Gnome projects</li>
1044</ul>
1045
1046<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1047<ul>
1048 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1049 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1050</ul>
1051
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1052<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1053<ul>
1054 <li>a purely bug fixes release</li>
1055 <li>fixed an encoding support problem when parsing from a memory block</li>
1056 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1057 <li>removed a bug in the function allowing to override the memory
1058 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1059</ul>
1060
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1061<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1062<ul>
1063 <li>applied a lot of portability fixes</li>
1064 <li>better encoding support/cleanup and saving (content is now always
1065 encoded in UTF-8)</li>
1066 <li>the HTML parser now correctly handles encodings</li>
1067 <li>added xmlHasProp()</li>
1068 <li>fixed a serious problem with &amp;#38;</li>
1069 <li>propagated the fix to FTP client</li>
1070 <li>cleanup, bugfixes, etc ...</li>
1071 <li>Added a page about <a href="encoding.html">libxml Internationalization
1072 support</a></li>
1073</ul>
1074
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1075<h3>1.8.9: July 9 2000</h3>
1076<ul>
1077 <li>fixed the spec the RPMs should be better</li>
1078 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1079 rpmfind users problem</li>
1080</ul>
1081
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1082<h3>2.1.1: July 1 2000</h3>
1083<ul>
1084 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1085 <li>improvements on the HTML parser</li>
1086</ul>
1087
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1088<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1089<ul>
1090 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
1091 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1092 about &amp;#38; charref parsing</li>
1093 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1094 also contains numerous fixes and enhancements:
1095 <ul>
1096 <li>added xmlStopParser() to stop parsing</li>
1097 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1098 <li>includes XPath patches provided by Picdar Technology</li>
1099 <li>tried to fix as much as possible DtD validation and namespace
1100 related problems</li>
1101 <li>output to a given encoding has been added/tested</li>
1102 <li>lot of various fixes</li>
1103 </ul>
1104 </li>
1105</ul>
1106
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1107<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1108<ul>
1109 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1110 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
1111 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
1112 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1113 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1114 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1115 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1116 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1117 <pre>#include "xxx.h"</pre>
1118 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1119 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1120 <li>the memory allocation routines used by libxml can now be overloaded
1121 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1122 <li>The previously CVS only tool tester has been renamed
1123 <strong>xmllint</strong> and is now installed as part of the libxml2
1124 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1125 <li>The I/O interface has been revamped. There is now ways to plug in
1126 specific I/O modules, either at the URI scheme detection level using
1127 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1128 parser context using xmlCreateIOParserCtxt()</li>
1129 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1130 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1131 <li>a number of optional features of libxml can now be excluded at
1132 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1133</ul>
1134
1135<h3>2.0.0beta: Mar 14 2000</h3>
1136<ul>
1137 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1138 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1139 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1140 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1141 <li>This version is now the head in the Gnome CVS base, the old one is
1142 available under the tag LIB_XML_1_X</li>
1143 <li>This includes a very large set of changes. Froma programmatic point of
1144 view applications should not have to be modified too much, check the <a
1145 href="upgrade.html">upgrade page</a></li>
1146 <li>Some interfaces may changes (especially a bit about encoding).</li>
1147 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1148 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1149 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1150 handled now</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1151 <li>Better handling of entities, especially well formedness checking
1152 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1153 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1154 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1155 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
1156 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1157 </ul>
1158 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1159 <li>Serious progress were made toward compliance, <a
1160 href="conf/result.html">here are the result of the test</a> against the
1161 OASIS testsuite (except the japanese tests since I don't support that
1162 encoding yet). This URL is rebuilt every couple of hours using the CVS
1163 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1164</ul>
1165
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1166<h3>1.8.7: Mar 6 2000</h3>
1167<ul>
1168 <li>This is a bug fix release:</li>
1169 <li>It is possible to disable the ignorable blanks heuristic used by
1170 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1171 that for adherence to XML spec, this behaviour will be disabled by
1172 default in 2.x . The same function will allow to keep compatibility for
1173 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1174 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1175 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1176 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1177 compilation on some platforms has been fixed</li>
1178 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1179 URIs</li>
1180</ul>
1181
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1182<h3>1.8.6: Jan 31 2000</h3>
1183<ul>
1184 <li>added a nanoFTP transport module, debugged until the new version of <a
1185 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1186 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1187</ul>
1188
1189<h3>1.8.5: Jan 21 2000</h3>
1190<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1191 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1192 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1193 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1194 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1195 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1196 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1197 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1198 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1199</ul>
1200
1201<h3>1.8.4: Jan 13 2000</h3>
1202<ul>
1203 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1204 <li>all exit() call should have been removed from libxml</li>
1205 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1206 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1207</ul>
1208
1209<h3>1.8.3: Jan 5 2000</h3>
1210<ul>
1211 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1212 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]1213 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1214 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1215 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1216 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1217 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1218 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1219 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1220</ul>
1221
1222<h3>1.8.2: Dec 21 1999</h3>
1223<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1224 <li>I got another problem with includes and C++, I hope this issue is fixed
1225 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1226 <li>Added a few tree modification functions: xmlReplaceNode,
1227 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1228 xmlDocSetRootElement</li>
1229 <li>Tried to improve the HTML output with help from <a
1230 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1231</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1232
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1233<h3>1.8.1: Dec 18 1999</h3>
1234<ul>
1235 <li>various patches to avoid troubles when using libxml with C++ compilers
1236 the "namespace" keyword and C escaping in include files</li>
1237 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1238 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1239 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1240 <li>fixed a posteriori validation (validation after parsing, or by using a
1241 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1242 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1243</ul>
1244
1245<h3>1.8.0: Dec 12 1999</h3>
1246<ul>
1247 <li>cleanup, especially memory wise</li>
1248 <li>the parser should be more reliable, especially the HTML one, it should
1249 not crash, whatever the input !</li>
1250 <li>Integrated various patches, especially a speedup improvement for large
1251 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1252 configure with --with-buffers to enable them.</li>
1253 <li>attribute normalization, oops should have been added long ago !</li>
1254 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
1255 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1256</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1257
1258<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1259<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1260 <li>Lots of HTML improvement</li>
1261 <li>Fixed some errors when saving both XML and HTML</li>
1262 <li>More examples, the regression tests should now look clean</li>
1263 <li>Fixed a bug with contiguous charref</li>
1264</ul>
1265
1266<h3>1.7.3: Sep 29 1999</h3>
1267<ul>
1268 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1269 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1270 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1271</ul>
1272
1273<h3>1.7.1: Sep 24 1999</h3>
1274<ul>
1275 <li>The basic type for strings manipulated by libxml has been renamed in
1276 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1277 is that CHAR was conflicting with a predefined type on Windows. However
1278 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1279 <strong>#define </strong>.</li>
1280 <li>Changed another error : the use of a structure field called errno, and
1281 leading to troubles on platforms where it's a macro</li>
1282</ul>
1283
1284<h3>1.7.0: sep 23 1999</h3>
1285<ul>
1286 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1287 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1288 <li>Added an errno to report errors by another mean than a simple printf
1289 like callback</li>
1290 <li>Finished ID/IDREF support and checking when validation</li>
1291 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1292 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1293 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1294 implementation</li>
1295 <li>Added an HTML parser front-end</li>
1296</ul>
1297
1298<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1299
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1300<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1301markup-based structured documents. Here is <a name="example">an example XML
1302document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1303<pre>&lt;?xml version="1.0"?&gt;
1304&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1305 &lt;head&gt;
1306 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1307 &lt;/head&gt;
1308 &lt;chapter&gt;
1309 &lt;title&gt;The Linux adventure&lt;/title&gt;
1310 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1311 &lt;image href="linus.gif"/&gt;
1312 &lt;p&gt;...&lt;/p&gt;
1313 &lt;/chapter&gt;
1314&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1315
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1316<p>The first line specifies that it's an XML document and gives useful
1317information about its encoding. Then the document is a text format whose
1318structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1319to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1320(no content), a single tag can serve as both the opening and closing tag if
1321it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1322that, for example, the image tag has no content (just an attribute) and is
1323closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1324
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1325<p>XML can be applied sucessfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1326structured document maintenance (where it follows the steps of SGML) to
1327simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1328spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1329it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1330
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1331<h2><a name="XSLT">XSLT</a></h2>
1332
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1333<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1334
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1335<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1336language for transforming XML documents into other XML documents (or
1337HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1338
1339<p>A separate library called libxslt is being built on top of libxml2. This
1340module "libxslt" can be found in the Gnome CVS base too.</p>
1341
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1342<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1343href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1344supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1345href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1346name="Changelog">Changelog</a></p>
1347
1348<h2><a name="Python">Python and bindings</a></h2>
1349
1350<p>There is a number of language bindings and wrappers available for libxml2,
1351the list below is not exhaustive. Please contact the <a
1352href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1353(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1354order to get updates to this list or to discuss the specific topic of libxml2
1355or libxslt wrappers or bindings:</p>
1356<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1357 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1358 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1359 Website: <a
1360 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1361 Download: <a
1362 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1363 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1364 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
1365 <li><a
1366 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1367 Sergeant</a> developped <a
1368 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
1369 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1370 application server</a></li>
1371 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1372 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1373 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1374 <li>Petr Kozelka provides <a
1375 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1376 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1377 <li>Uwe Fechner also provides <a
1378 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]1379 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1380 <li>Wai-Sun "Squidster" Chia provides <a
1381 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1382 libxml2 bindings are also available in Ruby through the <a
1383 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1384 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1385 <li>Steve Ball and contributors maintains <a
1386 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1387 Tcl</a></li>
1388 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1389</ul>
1390
1391<p>The distribution includes a set of Python bindings, which are garanteed to
1392be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1393interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1394
1395<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1396<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1397 <li>If you use an RPM based distribution, simply install the <a
1398 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1399 RPM</a> (and if needed the <a
1400 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1401 RPM</a>).</li>
1402 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1403 module distribution</a> corresponding to your installed version of
1404 libxml2 and libxslt. Note that to install it you will need both libxml2
1405 and libxslt installed and run "python setup.py build install" in the
1406 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1407</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1408
1409<p>The distribution includes a set of examples and regression tests for the
1410python bindings in the <code>python/tests</code> directory. Here are some
1411excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1412
1413<h3>tst.py:</h3>
1414
1415<p>This is a basic test of the file interface and DOM navigation:</p>
1416<pre>import libxml2
1417
1418doc = libxml2.parseFile("tst.xml")
1419if doc.name != "tst.xml":
1420 print "doc.name failed"
1421 sys.exit(1)
1422root = doc.children
1423if root.name != "doc":
1424 print "root.name failed"
1425 sys.exit(1)
1426child = root.children
1427if child.name != "foo":
1428 print "child.name failed"
1429 sys.exit(1)
1430doc.freeDoc()</pre>
1431
1432<p>The Python module is called libxml2, parseFile is the equivalent of
1433xmlParseFile (most of the bindings are automatically generated, and the xml
1434prefix is removed and the casing convention are kept). All node seen at the
1435binding level share the same subset of accesors:</p>
1436<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1437 <li><code>name</code> : returns the node name</li>
1438 <li><code>type</code> : returns a string indicating the node
1439 typ<code>e</code></li>
1440 <li><code>content</code> : returns the content of the node, it is based on
1441 xmlNodeGetContent() and hence is recursive.</li>
1442 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1443 <code>next</code>, <code>prev</code>, <code>doc</code>,
1444 <code>properties</code>: pointing to the associated element in the tree,
1445 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1446</ul>
1447
1448<p>Also note the need to explicitely deallocate documents with freeDoc() .
1449Reference counting for libxml2 trees would need quite a lot of work to
1450function properly, and rather than risk memory leaks if not implemented
1451correctly it sounds safer to have an explicit function to free a tree. The
1452wrapper python objects like doc, root or child are them automatically garbage
1453collected.</p>
1454
1455<h3>validate.py:</h3>
1456
1457<p>This test check the validation interfaces and redirection of error
1458messages:</p>
1459<pre>import libxml2
1460
1461#desactivate error messages from the validation
1462def noerr(ctx, str):
1463 pass
1464
1465libxml2.registerErrorHandler(noerr, None)
1466
1467ctxt = libxml2.createFileParserCtxt("invalid.xml")
1468ctxt.validate(1)
1469ctxt.parseDocument()
1470doc = ctxt.doc()
1471valid = ctxt.isValid()
1472doc.freeDoc()
1473if valid != 0:
1474 print "validity chec failed"</pre>
1475
1476<p>The first thing to notice is the call to registerErrorHandler(), it
1477defines a new error handler global to the library. It is used to avoid seeing
1478the error messages when trying to validate the invalid document.</p>
1479
1480<p>The main interest of that test is the creation of a parser context with
1481createFileParserCtxt() and how the behaviour can be changed before calling
1482parseDocument() . Similary the informations resulting from the parsing phase
1483are also available using context methods.</p>
1484
1485<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1486C function interfaces in terms of objects method as much as possible. The
1487best to get a complete view of what methods are supported is to look at the
1488libxml2.py module containing all the wrappers.</p>
1489
1490<h3>push.py:</h3>
1491
1492<p>This test show how to activate the push parser interface:</p>
1493<pre>import libxml2
1494
1495ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1496ctxt.parseChunk("/&gt;", 2, 1)
1497doc = ctxt.doc()
1498
1499doc.freeDoc()</pre>
1500
1501<p>The context is created with a speciall call based on the
1502xmlCreatePushParser() from the C library. The first argument is an optional
1503SAX callback object, then the initial set of data, the lenght and the name of
1504the resource in case URI-References need to be computed by the parser.</p>
1505
1506<p>Then the data are pushed using the parseChunk() method, the last call
1507setting the thrird argument terminate to 1.</p>
1508
1509<h3>pushSAX.py:</h3>
1510
1511<p>this test show the use of the event based parsing interfaces. In this case
1512the parser does not build a document, but provides callback information as
1513the parser makes progresses analyzing the data being provided:</p>
1514<pre>import libxml2
1515log = ""
1516
1517class callback:
1518 def startDocument(self):
1519 global log
1520 log = log + "startDocument:"
1521
1522 def endDocument(self):
1523 global log
1524 log = log + "endDocument:"
1525
1526 def startElement(self, tag, attrs):
1527 global log
1528 log = log + "startElement %s %s:" % (tag, attrs)
1529
1530 def endElement(self, tag):
1531 global log
1532 log = log + "endElement %s:" % (tag)
1533
1534 def characters(self, data):
1535 global log
1536 log = log + "characters: %s:" % (data)
1537
1538 def warning(self, msg):
1539 global log
1540 log = log + "warning: %s:" % (msg)
1541
1542 def error(self, msg):
1543 global log
1544 log = log + "error: %s:" % (msg)
1545
1546 def fatalError(self, msg):
1547 global log
1548 log = log + "fatalError: %s:" % (msg)
1549
1550handler = callback()
1551
1552ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1553chunk = " url='tst'&gt;b"
1554ctxt.parseChunk(chunk, len(chunk), 0)
1555chunk = "ar&lt;/foo&gt;"
1556ctxt.parseChunk(chunk, len(chunk), 1)
1557
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1558reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1559 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1560if log != reference:
1561 print "Error got: %s" % log
1562 print "Exprected: %s" % reference</pre>
1563
1564<p>The key object in that test is the handler, it provides a number of entry
1565points which can be called by the parser as it makes progresses to indicate
1566the information set obtained. The full set of callback is larger than what
1567the callback class in that specific example implements (see the SAX
1568definition for a complete list). The wrapper will only call those supplied by
1569the object when activated. The startElement receives the names of the element
1570and a dictionnary containing the attributes carried by this element.</p>
1571
1572<p>Also note that the reference string generated from the callback shows a
1573single character call even though the string "bar" is passed to the parser
1574from 2 different call to parseChunk()</p>
1575
1576<h3>xpath.py:</h3>
1577
1578<p>This is a basic test of XPath warppers support</p>
1579<pre>import libxml2
1580
1581doc = libxml2.parseFile("tst.xml")
1582ctxt = doc.xpathNewContext()
1583res = ctxt.xpathEval("//*")
1584if len(res) != 2:
1585 print "xpath query: wrong node set size"
1586 sys.exit(1)
1587if res[0].name != "doc" or res[1].name != "foo":
1588 print "xpath query: wrong node set value"
1589 sys.exit(1)
1590doc.freeDoc()
1591ctxt.xpathFreeContext()</pre>
1592
1593<p>This test parses a file, then create an XPath context to evaluate XPath
1594expression on it. The xpathEval() method execute an XPath query and returns
1595the result mapped in a Python way. String and numbers are natively converted,
1596and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
1597the document, the XPath context need to be freed explicitely, also not that
1598the result of the XPath query may point back to the document tree and hence
1599the document must be freed after the result of the query is used.</p>
1600
1601<h3>xpathext.py:</h3>
1602
1603<p>This test shows how to extend the XPath engine with functions written in
1604python:</p>
1605<pre>import libxml2
1606
1607def foo(ctx, x):
1608 return x + 1
1609
1610doc = libxml2.parseFile("tst.xml")
1611ctxt = doc.xpathNewContext()
1612libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1613res = ctxt.xpathEval("foo(1)")
1614if res != 2:
1615 print "xpath extension failure"
1616doc.freeDoc()
1617ctxt.xpathFreeContext()</pre>
1618
1619<p>Note how the extension function is registered with the context (but that
1620part is not yet finalized, ths may change slightly in the future).</p>
1621
1622<h3>tstxpath.py:</h3>
1623
1624<p>This test is similar to the previousone but shows how the extension
1625function can access the XPath evaluation context:</p>
1626<pre>def foo(ctx, x):
1627 global called
1628
1629 #
1630 # test that access to the XPath evaluation contexts
1631 #
1632 pctxt = libxml2.xpathParserContext(_obj=ctx)
1633 ctxt = pctxt.context()
1634 called = ctxt.function()
1635 return x + 1</pre>
1636
1637<p>All the interfaces around the XPath parser(or rather evaluation) context
1638are not finalized, but it should be sufficient to do contextual work at the
1639evaluation point.</p>
1640
1641<h3>Memory debugging:</h3>
1642
1643<p>last but not least, all tests starts with the following prologue:</p>
1644<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1645libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1646
1647<p>and ends with the following epilogue:</p>
1648<pre>#memory debug specific
1649libxml2.cleanupParser()
1650if libxml2.debugMemory(1) == 0:
1651 print "OK"
1652else:
1653 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1654 libxml2.dumpMemory()</pre>
1655
1656<p>Those activate the memory debugging interface of libxml2 where all
1657alloacted block in the library are tracked. The prologue then cleans up the
1658library state and checks that all allocated memory has been freed. If not it
1659calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1660
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1661<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1662
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1663<p>Libxml is made of multiple components; some of them are optional, and most
1664of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1665<ul>
1666 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1667 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1668 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1669 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1670 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1671 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1672 <li>a SAX tree module to build an in-memory DOM representation</li>
1673 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1674 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1675 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1676 (optional)</li>
1677 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1678</ul>
1679
1680<p>Graphically this gives the following:</p>
1681
1682<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1683
1684<p></p>
1685
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1686<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1687
1688<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1689returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1690<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1691as the file name, the document type, and a <strong>children</strong> pointer
1692which is the root of the document (or more exactly the first child under the
1693root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1694chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1695relationship. An xmlNode can also carry properties (a chain of xmlAttr
1696structures). An attribute may have a value which is a list of TEXT or
1697ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1698
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1699<p>Here is an example (erroneous with respect to the XML spec since there
1700should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1701
1702<p><img src="structure.gif" alt=" structure.gif "></p>
1703
1704<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1705called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1706prints them back as parsed. This is useful for detecting errors both in XML
1707code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1708which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1709result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1710<pre>DOCUMENT
1711version=1.0
1712standalone=true
1713 ELEMENT EXAMPLE
1714 ATTRIBUTE prop1
1715 TEXT
1716 content=gnome is great
1717 ATTRIBUTE prop2
1718 ENTITY_REF
1719 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1720 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1721 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1722 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1723 TEXT
1724 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1725 ELEMENT chapter
1726 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1727 TEXT
1728 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1729 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1730 TEXT
1731 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1732 ELEMENT image
1733 ATTRIBUTE href
1734 TEXT
1735 content=linus.gif
1736 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1737 TEXT
1738 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1739
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1740<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1741
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1742<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1743
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1744<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1745memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1746loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1747a <strong>callback-based interface</strong> to the parser. Before parsing,
1748the application layer registers a customized set of callbacks which are
1749called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1750
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1751<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1752libxml, see the <a
1753href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1754documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1755Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1756
1757<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1758program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1759binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1760distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1761testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1762<pre>SAX.setDocumentLocator()
1763SAX.startDocument()
1764SAX.getEntity(amp)
1765SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1766SAX.characters( , 3)
1767SAX.startElement(head)
1768SAX.characters( , 4)
1769SAX.startElement(title)
1770SAX.characters(Welcome to Gnome, 16)
1771SAX.endElement(title)
1772SAX.characters( , 3)
1773SAX.endElement(head)
1774SAX.characters( , 3)
1775SAX.startElement(chapter)
1776SAX.characters( , 4)
1777SAX.startElement(title)
1778SAX.characters(The Linux adventure, 19)
1779SAX.endElement(title)
1780SAX.characters( , 4)
1781SAX.startElement(p)
1782SAX.characters(bla bla bla ..., 15)
1783SAX.endElement(p)
1784SAX.characters( , 4)
1785SAX.startElement(image, href='linus.gif')
1786SAX.endElement(image)
1787SAX.characters( , 4)
1788SAX.startElement(p)
1789SAX.characters(..., 3)
1790SAX.endElement(p)
1791SAX.characters( , 3)
1792SAX.endElement(chapter)
1793SAX.characters( , 1)
1794SAX.endElement(EXAMPLE)
1795SAX.endDocument()</pre>
1796
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1797<p>Most of the other interfaces of libxml are based on the DOM tree-building
1798facility, so nearly everything up to the end of this document presupposes the
1799use of the standard DOM tree build. Note that the DOM tree itself is built by
1800a set of registered default callbacks, without internal specific
1801interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1802
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1803<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1804
1805<p>Table of Content:</p>
1806<ol>
1807 <li><a href="#General5">General overview</a></li>
1808 <li><a href="#definition">The definition</a></li>
1809 <li><a href="#Simple">Simple rules</a>
1810 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1811 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1812 <li><a href="#Declaring">Declaring elements</a></li>
1813 <li><a href="#Declaring1">Declaring attributes</a></li>
1814 </ol>
1815 </li>
1816 <li><a href="#Some">Some examples</a></li>
1817 <li><a href="#validate">How to validate</a></li>
1818 <li><a href="#Other">Other resources</a></li>
1819</ol>
1820
1821<h3><a name="General5">General overview</a></h3>
1822
1823<p>Well what is validation and what is a DTD ?</p>
1824
1825<p>DTD is the acronym for Document Type Definition. This is a description of
1826the content for a familly of XML files. This is part of the XML 1.0
1827specification, and alows to describe and check that a given document instance
1828conforms to a set of rules detailing its structure and content.</p>
1829
1830<p>Validation is the process of checking a document against a DTD (more
1831generally against a set of construction rules).</p>
1832
1833<p>The validation process and building DTDs are the two most difficult parts
1834of the XML life cycle. Briefly a DTD defines all the possibles element to be
1835found within your document, what is the formal shape of your document tree
1836(by defining the allowed content of an element, either text, a regular
1837expression for the allowed list of children, or mixed content i.e. both text
1838and children). The DTD also defines the allowed attributes for all elements
1839and the types of the attributes.</p>
1840
1841<h3><a name="definition1">The definition</a></h3>
1842
1843<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1844href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1845Rev1</a>):</p>
1846<ul>
1847 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1848 elements</a></li>
1849 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1850 attributes</a></li>
1851</ul>
1852
1853<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1854ancient...</p>
1855
1856<h3><a name="Simple1">Simple rules</a></h3>
1857
1858<p>Writing DTD can be done in multiple ways, the rules to build them if you
1859need something fixed or something which can evolve over time can be radically
1860different. Really complex DTD like Docbook ones are flexible but quite harder
1861to design. I will just focuse on DTDs for a formats with a fixed simple
1862structure. It is just a set of basic rules, and definitely not exhaustive nor
1863useable for complex DTD design.</p>
1864
1865<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1866
1867<p>Assuming the top element of the document is <code>spec</code> and the dtd
1868is placed in the file <code>mydtd</code> in the subdirectory
1869<code>dtds</code> of the directory from where the document were loaded:</p>
1870
1871<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1872
1873<p>Notes:</p>
1874<ul>
1875 <li>the system string is actually an URI-Reference (as defined in <a
1876 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1877 full URL string indicating the location of your DTD on the Web, this is a
1878 really good thing to do if you want others to validate your document</li>
1879 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
1880 magic string) so that the DTd is looked up in catalogs on the client side
1881 without having to locate it on the web</li>
1882 <li>a dtd contains a set of elements and attributes declarations, but they
1883 don't define what the root of the document should be. This is explicitely
1884 told to the parser/validator as the first element of the
1885 <code>DOCTYPE</code> declaration.</li>
1886</ul>
1887
1888<h4><a name="Declaring2">Declaring elements</a>:</h4>
1889
1890<p>The following declares an element <code>spec</code>:</p>
1891
1892<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1893
1894<p>it also expresses that the spec element contains one <code>front</code>,
1895one <code>body</code> and one optionnal <code>back</code> children elements
1896in this order. The declaration of one element of the structure and its
1897content are done in a single declaration. Similary the following declares
1898<code>div1</code> elements:</p>
1899
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1900<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1901
1902<p>means div1 contains one <code>head</code> then a series of optional
1903<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1904optional <code>div2</code>. And last but not least an element can contain
1905text:</p>
1906
1907<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1908
1909<p><code>b</code> contains text or being of mixed content (text and elements
1910in no particular order):</p>
1911
1912<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1913
1914<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1915<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1916order.</p>
1917
1918<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1919
1920<p>again the attributes declaration includes their content definition:</p>
1921
1922<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1923
1924<p>means that the element <code>termdef</code> can have a <code>name</code>
1925attribute containing text (<code>CDATA</code>) and which is optionnal
1926(<code>#IMPLIED</code>). The attribute value can also be defined within a
1927set:</p>
1928
1929<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1930"ordered"&gt;</code></p>
1931
1932<p>means <code>list</code> element have a <code>type</code> attribute with 3
1933allowed values "bullets", "ordered" or "glossary" and which default to
1934"ordered" if the attribute is not explicitely specified.</p>
1935
1936<p>The content type of an attribute can be text (<code>CDATA</code>),
1937anchor/reference/references
1938(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1939(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1940(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1941<code>chapter</code> element can have an optional <code>id</code> attribute
1942of type <code>ID</code>, usable for reference from attribute of type
1943IDREF:</p>
1944
1945<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1946
1947<p>The last value of an attribute definition can be <code>#REQUIRED
1948</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1949meaning that it is optional, or the default value (possibly prefixed by
1950<code>#FIXED</code> if it is the only allowed).</p>
1951
1952<p>Notes:</p>
1953<ul>
1954 <li>usually the attributes pertaining to a given element are declared in a
1955 single expression, but it is just a convention adopted by a lot of DTD
1956 writers:
1957 <pre>&lt;!ATTLIST termdef
1958 id ID #REQUIRED
1959 name CDATA #IMPLIED&gt;</pre>
1960 <p>The previous construct defines both <code>id</code> and
1961 <code>name</code> attributes for the element <code>termdef</code></p>
1962 </li>
1963</ul>
1964
1965<h3><a name="Some1">Some examples</a></h3>
1966
1967<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
1968contains some complex DTD examples. The <code>test/valid/dia.xml</code>
1969example shows an XML file where the simple DTD is directly included within
1970the document.</p>
1971
1972<h3><a name="validate1">How to validate</a></h3>
1973
1974<p>The simplest is to use the xmllint program comming with libxml. The
1975<code>--valid</code> option turn on validation of the files given as input,
1976for example the following validates a copy of the first revision of the XML
19771.0 specification:</p>
1978
1979<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
1980
1981<p>the -- noout is used to not output the resulting tree.</p>
1982
1983<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
1984a given DTD.</p>
1985
1986<p>Libxml exports an API to handle DTDs and validation, check the <a
1987href="http://xmlsoft.org/html/libxml-valid.html">associated
1988description</a>.</p>
1989
1990<h3><a name="Other1">Other resources</a></h3>
1991
1992<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
1993will just list one for now, others pointers welcome:</p>
1994<ul>
1995 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
1996</ul>
1997
1998<p>I suggest looking at the examples found under test/valid/dtd and any of
1999the large number of books available on XML. The dia example in test/valid
2000should be both simple and complete enough to allow you to build your own.</p>
2001
2002<p></p>
2003
2004<h2><a name="Memory">Memory Management</a></h2>
2005
2006<p>Table of Content:</p>
2007<ol>
2008 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2009 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2010 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2011 <li><a href="#Debugging">Debugging routines</a></li>
2012 <li><a href="#General4">General memory requirements</a></li>
2013</ol>
2014
2015<h3><a name="General3">General overview</a></h3>
2016
2017<p>The module <code><a
2018href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2019provides the interfaces to the libxml memory system:</p>
2020<ul>
2021 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2022 xmlMalloc() and xmlRealloc()</li>
2023 <li>those routines can be reallocated to a specific set of routine, by
2024 default the libc ones i.e. free(), malloc() and realloc()</li>
2025 <li>the xmlmemory.c module includes a set of debugging routine</li>
2026</ul>
2027
2028<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2029
2030<p>It is sometimes useful to not use the default memory allocator, either for
2031debugging, analysis or to implement a specific behaviour on memory management
2032(like on embedded systems). Two function calls are available to do so:</p>
2033<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2034 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2035 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2036 <li><a
2037 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2038 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2039</ul>
2040
2041<p>Of course a call to xmlMemSetup() should probably be done before calling
2042any other libxml routines (unless you are sure your allocations routines are
2043compatibles).</p>
2044
2045<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2046
2047<p>Libxml is not stateless, there is a few set of memory structures needing
2048allocation before the parser is fully functionnal (some encoding structures
2049for example). This also mean that once parsing is finished there is a tiny
2050amount of memory (a few hundred bytes) which can be recollected if you don't
2051reuse the parser immediately:</p>
2052<ul>
2053 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2054 ()</a> is a centralized routine to free the parsing states. Note that it
2055 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2056 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2057 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2058 ()</a> is the dual routine allowing to preallocate the parsing state
2059 which can be useful for example to avoid initialization reentrancy
2060 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2061</ul>
2062
2063<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2064at the next invocation of parser routines, but be careful of the consequences
2065in multithreaded applications.</p>
2066
2067<h3><a name="Debugging">Debugging routines</a></h3>
2068
2069<p>When configured using --with-mem-debug flag (off by default), libxml uses
2070a set of memory allocation debugging routineskeeping track of all allocated
2071blocks and the location in the code where the routine was called. A couple of
2072other debugging routines allow to dump the memory allocated infos to a file
2073or call a specific routine when a given block number is allocated:</p>
2074<ul>
2075 <li><a
2076 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2077 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2078 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2079 and <a
2080 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2081 are the memory debugging replacement allocation routines</li>
2082 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2083 ()</a> dumps all the informations about the allocated memory block lefts
2084 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2085</ul>
2086
2087<p>When developping libxml memory debug is enabled, the tests programs call
2088xmlMemoryDump () and the "make test" regression tests will check for any
2089memory leak during the full regression test sequence, this helps a lot
2090ensuring that libxml does not leak memory and bullet proof memory
2091allocations use (some libc implementations are known to be far too permissive
2092resulting in major portability problems!).</p>
2093
2094<p>If the .memdump reports a leak, it displays the allocation function and
2095also tries to give some informations about the content and structure of the
2096allocated blocks left. This is sufficient in most cases to find the culprit,
2097but not always. Assuming the allocation problem is reproductible, it is
2098possible to find more easilly:</p>
2099<ol>
2100 <li>write down the block number xxxx not allocated</li>
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2101 <li>export the environement variable XML_MEM_BREAKPOINT=xxxx , the easiest
2102 when using GDB is to simply give the command
2103 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2104 <p>before running the program.</p>
2105 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2106 <li>run the program under a debugger and set a breakpoint on
2107 xmlMallocBreakpoint() a specific function called when this precise block
2108 is allocated</li>
2109 <li>when the breakpoint is reached you can then do a fine analysis of the
2110 allocation an step to see the condition resulting in the missing
2111 deallocation.</li>
2112</ol>
2113
2114<p>I used to use a commercial tool to debug libxml memory problems but after
2115noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2116used and proved extremely efficient until now. Lately I have also used <a
2117href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2118success, it is tied to the i386 architecture since it works by emulating the
2119processor and instruction set, it is slow but extremely efficient, i.e. it
2120spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2121
2122<h3><a name="General4">General memory requirements</a></h3>
2123
2124<p>How much libxml memory require ? It's hard to tell in average it depends
2125of a number of things:</p>
2126<ul>
2127 <li>the parser itself should work in a fixed amout of memory, except for
2128 information maintained about the stacks of names and entities locations.
2129 The I/O and encoding handlers will probably account for a few KBytes.
2130 This is true for both the XML and HTML parser (though the HTML parser
2131 need more state).</li>
2132 <li>If you are generating the DOM tree then memory requirements will grow
2133 nearly lineary with the size of the data. In general for a balanced
2134 textual document the internal memory requirement is about 4 times the
2135 size of the UTF8 serialization of this document (exmple the XML-1.0
2136 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2137 memory when parsed). Validation will add a amount of memory required for
2138 maintaining the external Dtd state which should be linear with the
2139 complexity of the content model defined by the Dtd</li>
2140 <li>If you don't care about the advanced features of libxml like
2141 validation, DOM, XPath or XPointer, but really need to work fixed memory
2142 requirements, then the SAX interface should be used.</li>
2143</ul>
2144
2145<p></p>
2146
2147<h2><a name="Encodings">Encodings support</a></h2>
2148
2149<p>Table of Content:</p>
2150<ol>
2151 <li><a href="encoding.html#What">What does internationalization support
2152 mean ?</a></li>
2153 <li><a href="encoding.html#internal">The internal encoding, how and
2154 why</a></li>
2155 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2156 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2157 <li><a href="encoding.html#extend">How to extend the existing
2158 support</a></li>
2159</ol>
2160
2161<h3><a name="What">What does internationalization support mean ?</a></h3>
2162
2163<p>XML was designed from the start to allow the support of any character set
2164by using Unicode. Any conformant XML parser has to support the UTF-8 and
2165UTF-16 default encodings which can both express the full unicode ranges. UTF8
2166is a variable length encoding whose greatest point are to resuse the same
2167emcoding for ASCII and to save space for Western encodings, but it is a bit
2168more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2169sometimes combines two pairs), it makes implementation easier, but looks a
2170bit overkill for Western languages encoding. Moreover the XML specification
2171allows document to be encoded in other encodings at the condition that they
2172are clearly labelled as such. For example the following is a wellformed XML
2173document encoded in ISO-8859 1 and using accentuated letter that we French
2174likes for both markup and content:</p>
2175<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2176&lt;très&gt;là&lt;/très&gt;</pre>
2177
2178<p>Having internationalization support in libxml means the foolowing:</p>
2179<ul>
2180 <li>the document is properly parsed</li>
2181 <li>informations about it's encoding are saved</li>
2182 <li>it can be modified</li>
2183 <li>it can be saved in its original encoding</li>
2184 <li>it can also be saved in another encoding supported by libxml (for
2185 example straight UTF8 or even an ASCII form)</li>
2186</ul>
2187
2188<p>Another very important point is that the whole libxml API, with the
2189exception of a few routines to read with a specific encoding or save to a
2190specific encoding, is completely agnostic about the original encoding of the
2191document.</p>
2192
2193<p>It should be noted too that the HTML parser embedded in libxml now obbey
2194the same rules too, the following document will be (as of 2.2.2) handled in
2195an internationalized fashion by libxml too:</p>
2196<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2197 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2198&lt;html lang="fr"&gt;
2199&lt;head&gt;
2200 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2201&lt;/head&gt;
2202&lt;body&gt;
2203&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2204&lt;/html&gt;</pre>
2205
2206<h3><a name="internal">The internal encoding, how and why</a></h3>
2207
2208<p>One of the core decision was to force all documents to be converted to a
2209default internal encoding, and that encoding to be UTF-8, here are the
2210rationale for those choices:</p>
2211<ul>
2212 <li>keeping the native encoding in the internal form would force the libxml
2213 users (or the code associated) to be fully aware of the encoding of the
2214 original document, for examples when adding a text node to a document,
2215 the content would have to be provided in the document encoding, i.e. the
2216 client code would have to check it before hand, make sure it's conformant
2217 to the encoding, etc ... Very hard in practice, though in some specific
2218 cases this may make sense.</li>
2219 <li>the second decision was which encoding. From the XML spec only UTF8 and
2220 UTF16 really makes sense as being the two only encodings for which there
2221 is amndatory support. UCS-4 (32 bits fixed size encoding) could be
2222 considered an intelligent choice too since it's a direct Unicode mapping
2223 support. I selected UTF-8 on the basis of efficiency and compatibility
2224 with surrounding software:
2225 <ul>
2226 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2227 more costly to import and export CPU wise) is also far more compact
2228 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2229 for right now (RPM RDF catalogs, advogato data, various configuration
2230 file formats, etc.) and the key point for today's computer
2231 architecture is efficient uses of caches. If one nearly double the
2232 memory requirement to store the same amount of data, this will trash
2233 caches (main memory/external caches/internal caches) and my take is
2234 that this harms the system far more than the CPU requirements needed
2235 for the conversion to UTF-8</li>
2236 <li>Most of libxml version 1 users were using it with straight ASCII
2237 most of the time, doing the conversion with an internal encoding
2238 requiring all their code to be rewritten was a serious show-stopper
2239 for using UTF-16 or UCS-4.</li>
2240 <li>UTF-8 is being used as the de-facto internal encoding standard for
2241 related code like the <a href="http://www.pango.org/">pango</a>
2242 upcoming Gnome text widget, and a lot of Unix code (yep another place
2243 where Unix programmer base takes a different approach from Microsoft
2244 - they are using UTF-16)</li>
2245 </ul>
2246 </li>
2247</ul>
2248
2249<p>What does this mean in practice for the libxml user:</p>
2250<ul>
2251 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2252 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2253 is simply to append 0 byte, as usual.</li>
2254 <li>One just need to make sure that when using chars outside the ASCII set,
2255 the values has been properly converted to UTF-8</li>
2256</ul>
2257
2258<h3><a name="implemente">How is it implemented ?</a></h3>
2259
2260<p>Let's describe how all this works within libxml, basically the I18N
2261(internationalization) support get triggered only during I/O operation, i.e.
2262when reading a document or saving one. Let's look first at the reading
2263sequence:</p>
2264<ol>
2265 <li>when a document is processed, we usually don't know the encoding, a
2266 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2267 ASCII range (0-0x7F) maps with ASCII</li>
2268 <li>the xml declaration if available is parsed, including the encoding
2269 declaration. At that point, if the autodetected encoding is different
2270 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2271 <li>If there is no encoding declaration, then the input has to be in either
2272 UTF-8 or UTF-16, if it is not then at some point when processing the
2273 input, the converter/checker of UTF-8 form will raise an encoding error.
2274 You may end-up with a garbled document, or no document at all ! Example:
2275 <pre>~/XML -&gt; ./xmllint err.xml
2276err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2277&lt;très&gt;là&lt;/très&gt;
2278 ^
2279err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2280&lt;très&gt;là&lt;/très&gt;
2281 ^</pre>
2282 </li>
2283 <li>xmlSwitchEncoding() does an encoding name lookup, canonalize it, and
2284 then search the default registered encoding converters for that encoding.
2285 If it's not within the default set and iconv() support has been compiled
2286 it, it will ask iconv for such an encoder. If this fails then the parser
2287 will report an error and stops processing:
2288 <pre>~/XML -&gt; ./xmllint err2.xml
2289err2.xml:1: error: Unsupported encoding UnsupportedEnc
2290&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2291 ^</pre>
2292 </li>
2293 <li>From that point the encoder process progressingly the input (it is
2294 plugged as a front-end to the I/O module) for that entity. It captures
2295 and convert on-the-fly the document to be parsed to UTF-8. The parser
2296 itself just does UTF-8 checking of this input and process it
2297 transparently. The only difference is that the encoding information has
2298 been added to the parsing context (more precisely to the input
2299 corresponding to this entity).</li>
2300 <li>The result (when using DOM) is an internal form completely in UTF-8
2301 with just an encoding information on the document node.</li>
2302</ol>
2303
2304<p>Ok then what's happen when saving the document (assuming you
2305colllected/built an xmlDoc DOM like structure) ? It depends on the function
2306called, xmlSaveFile() will just try to save in the original encoding, while
2307xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2308encoding:</p>
2309<ol>
2310 <li>if no encoding is given, libxml will look for an encoding value
2311 associated to the document and if it exists will try to save to that
2312 encoding,
2313 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2314 </li>
2315 <li>so if an encoding was specified, either at the API level or on the
2316 document, libxml will again canonalize the encoding name, lookup for a
2317 converter in the registered set or through iconv. If not found the
2318 function will return an error code</li>
2319 <li>the converter is placed before the I/O buffer layer, as another kind of
2320 buffer, then libxml will simply push the UTF-8 serialization to through
2321 that buffer, which will then progressively be converted and pushed onto
2322 the I/O layer.</li>
2323 <li>It is possible that the converter code fails on some input, for example
2324 trying to push an UTF-8 encoded chinese character through the UTF-8 to
2325 ISO-8859-1 converter won't work. Since the encoders are progressive they
2326 will just report the error and the number of bytes converted, at that
2327 point libxml will decode the offending character, remove it from the
2328 buffer and replace it with the associated charRef encoding &amp;#123; and
2329 resume the convertion. This guarante that any document will be saved
2330 without losses (except for markup names where this is not legal, this is
2331 a problem in the current version, in pactice avoid using non-ascci
2332 characters for tags or attributes names @@). A special "ascii" encoding
2333 name is used to save documents to a pure ascii form can be used when
2334 portability is really crucial</li>
2335</ol>
2336
2337<p>Here is a few examples based on the same test document:</p>
2338<pre>~/XML -&gt; ./xmllint isolat1
2339&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2340&lt;très&gt;là&lt;/très&gt;
2341~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2342&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2343&lt;très&gt;là  &lt;/très&gt;
2344~/XML -&gt; </pre>
2345
2346<p>The same processing is applied (and reuse most of the code) for HTML I18N
2347processing. Looking up and modifying the content encoding is a bit more
2348difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2349so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2350been provided. The parser also attempts to switch encoding on the fly when
2351detecting such a tag on input. Except for that the processing is the same
2352(and again reuses the same code).</p>
2353
2354<h3><a name="Default">Default supported encodings</a></h3>
2355
2356<p>libxml has a set of default converters for the following encodings
2357(located in encoding.c):</p>
2358<ol>
2359 <li>UTF-8 is supported by default (null handlers)</li>
2360 <li>UTF-16, both little and big endian</li>
2361 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2362 <li>ASCII, useful mostly for saving</li>
2363 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2364 predefined entities like &amp;copy; for the Copyright sign.</li>
2365</ol>
2366
2367<p>More over when compiled on an Unix platfor with iconv support the full set
2368of encodings supported by iconv can be instantly be used by libxml. On a
2369linux machine with glibc-2.1 the list of supported encodings and aliases fill
23703 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2371various Japanese ones.</p>
2372
2373<h4>Encoding aliases</h4>
2374
2375<p>From 2.2.3, libxml has support to register encoding names aliases. The
2376goal is to be able to parse document whose encoding is supported but where
2377the name differs (for example from the default set of names accepted by
2378iconv). The following functions allow to register and handle new aliases for
2379existing encodings. Once registered libxml will automatically lookup the
2380aliases when handling a document:</p>
2381<ul>
2382 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2383 <li>int xmlDelEncodingAlias(const char *alias);</li>
2384 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2385 <li>void xmlCleanupEncodingAliases(void);</li>
2386</ul>
2387
2388<h3><a name="extend">How to extend the existing support</a></h3>
2389
2390<p>Well adding support for new encoding, or overriding one of the encoders
2391(assuming it is buggy) should not be hard, just write an input and output
2392conversion routines to/from UTF-8, and register them using
2393xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2394called automatically if the parser(s) encounter such an encoding name
2395(register it uppercase, this will help). The description of the encoders,
2396their arguments and expected return values are described in the encoding.h
2397header.</p>
2398
2399<p>A quick note on the topic of subverting the parser to use a different
2400internal encoding than UTF-8, in some case people will absolutely want to
2401keep the internal encoding different, I think it's still possible (but the
2402encoding must be compliant with ASCII on the same subrange) though I didn't
2403tried it. The key is to override the default conversion routines (by
2404registering null encoders/decoders for your charsets), and bypass the UTF-8
2405checking of the parser by setting the parser context charset
2406(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
2407there is no guarantee taht this will work. You may also have some troubles
2408saving back.</p>
2409
2410<p>Basically proper I18N support is important, this requires at least
2411libxml-2.0.0, but a lot of features and corrections are really available only
2412starting 2.2.</p>
2413
2414<h2><a name="IO">I/O Interfaces</a></h2>
2415
2416<p>Table of Content:</p>
2417<ol>
2418 <li><a href="#General1">General overview</a></li>
2419 <li><a href="#basic">The basic buffer type</a></li>
2420 <li><a href="#Input">Input I/O handlers</a></li>
2421 <li><a href="#Output">Output I/O handlers</a></li>
2422 <li><a href="#entities">The entities loader</a></li>
2423 <li><a href="#Example2">Example of customized I/O</a></li>
2424</ol>
2425
2426<h3><a name="General1">General overview</a></h3>
2427
2428<p>The module <code><a
2429href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2430the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2431<ul>
2432 <li>Entities loader, this is a routine which tries to fetch the entities
2433 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2434 don't look at the public identifier since libxml do not maintain a
2435 catalog. You can redefine you own entity loader by using
2436 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2437 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2438 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2439 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2440 input layer to handle fetching the informations to feed the parser. This
2441 provides buffering and is also a placeholder where the encoding
2442 convertors to UTF8 are piggy-backed.</li>
2443 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2444 task but when generating a serialization from a tree.</li>
2445 <li>A mechanism to register sets of I/O callbacks and associate them with
2446 specific naming schemes like the protocol part of the URIs.
2447 <p>This affect the default I/O operations and allows to use specific I/O
2448 handlers for certain names.</p>
2449 </li>
2450</ul>
2451
2452<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2453example in the HTML parser is the following:</p>
2454<ol>
2455 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2456 the parsing context and the URI string.</li>
2457 <li>the URI string is checked against the existing registered handlers
2458 using their match() callback function, if the HTTP module was compiled
2459 in, it is registered and its match() function will succeeds</li>
2460 <li>the open() function of the handler is called and if successful will
2461 return an I/O Input buffer</li>
2462 <li>the parser will the start reading from this buffer and progressively
2463 fetch information from the resource, calling the read() function of the
2464 handler until the resource is exhausted</li>
2465 <li>if an encoding change is detected it will be installed on the input
2466 buffer, providing buffering and efficient use of the conversion
2467 routines</li>
2468 <li>once the parser has finished, the close() function of the handler is
2469 called once and the Input buffer and associed resources are
2470 deallocated.</li>
2471</ol>
2472
2473<p>The user defined callbacks are checked first to allow overriding of the
2474default libxml I/O routines.</p>
2475
2476<h3><a name="basic">The basic buffer type</a></h3>
2477
2478<p>All the buffer manipulation handling is done using the
2479<code>xmlBuffer</code> type define in <code><a
2480href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2481resizable memory buffer. The buffer allocation strategy can be selected to be
2482either best-fit or use an exponential doubling one (CPU vs. memory use
2483tradeoff). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
2484<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2485system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2486of functions allows to manipulate buffers with names starting with the
2487<code>xmlBuffer...</code> prefix.</p>
2488
2489<h3><a name="Input">Input I/O handlers</a></h3>
2490
2491<p>An Input I/O handler is a simple structure
2492<code>xmlParserInputBuffer</code> containing a context associated to the
2493resource (file descriptor, or pointer to a protocol handler), the read() and
2494close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2495encoding handler are also present to support charset conversion when
2496needed.</p>
2497
2498<h3><a name="Output">Output I/O handlers</a></h3>
2499
2500<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2501Input one except the callbacks are write() and close().</p>
2502
2503<h3><a name="entities">The entities loader</a></h3>
2504
2505<p>The entity loader resolves requests for new entities and create inputs for
2506the parser. Creating an input from a filename or an URI string is done
2507through the xmlNewInputFromFile() routine. The default entity loader do not
2508handle the PUBLIC identifier associated with an entity (if any). So it just
2509calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2510XML).</p>
2511
2512<p>If you want to hook up a catalog mechanism then you simply need to
2513override the default entity loader, here is an example:</p>
2514<pre>#include &lt;libxml/xmlIO.h&gt;
2515
2516xmlExternalEntityLoader defaultLoader = NULL;
2517
2518xmlParserInputPtr
2519xmlMyExternalEntityLoader(const char *URL, const char *ID,
2520 xmlParserCtxtPtr ctxt) {
2521 xmlParserInputPtr ret;
2522 const char *fileID = NULL;
2523 /* lookup for the fileID depending on ID */
2524
2525 ret = xmlNewInputFromFile(ctxt, fileID);
2526 if (ret != NULL)
2527 return(ret);
2528 if (defaultLoader != NULL)
2529 ret = defaultLoader(URL, ID, ctxt);
2530 return(ret);
2531}
2532
2533int main(..) {
2534 ...
2535
2536 /*
2537 * Install our own entity loader
2538 */
2539 defaultLoader = xmlGetExternalEntityLoader();
2540 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2541
2542 ...
2543}</pre>
2544
2545<h3><a name="Example2">Example of customized I/O</a></h3>
2546
2547<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2548real use case</a>, xmlDocDump() closes the FILE * passed by the application
2549and this was a problem. The <a
2550href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2551new output handler with the closing call deactivated:</p>
2552<ol>
2553 <li>First define a new I/O ouput allocator where the output don't close the
2554 file:
2555 <pre>xmlOutputBufferPtr
2556xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2557    xmlOutputBufferPtr ret;
2558    
2559    if (xmlOutputCallbackInitialized == 0)
2560        xmlRegisterDefaultOutputCallbacks();
2561
2562    if (file == NULL) return(NULL);
2563    ret = xmlAllocOutputBuffer(encoder);
2564    if (ret != NULL) {
2565        ret-&gt;context = file;
2566        ret-&gt;writecallback = xmlFileWrite;
2567        ret-&gt;closecallback = NULL; /* No close callback */
2568    }
2569    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2570
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2571
2572
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2573
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2574
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2575
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]2576
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]2577
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame^]2578
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2579} </pre>
2580 </li>
2581 <li>And then use it to save the document:
2582 <pre>FILE *f;
2583xmlOutputBufferPtr output;
2584xmlDocPtr doc;
2585int res;
2586
2587f = ...
2588doc = ....
2589
2590output = xmlOutputBufferCreateOwn(f, NULL);
2591res = xmlSaveFileTo(output, doc, NULL);
2592 </pre>
2593 </li>
2594</ol>
2595
2596<h2><a name="Catalog">Catalog support</a></h2>
2597
2598<p>Table of Content:</p>
2599<ol>
2600 <li><a href="General2">General overview</a></li>
2601 <li><a href="#definition">The definition</a></li>
2602 <li><a href="#Simple">Using catalogs</a></li>
2603 <li><a href="#Some">Some examples</a></li>
2604 <li><a href="#reference">How to tune catalog usage</a></li>
2605 <li><a href="#validate">How to debug catalog processing</a></li>
2606 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2607 <li><a href="#implemento">The implementor corner quick review of the
2608 API</a></li>
2609 <li><a href="#Other">Other resources</a></li>
2610</ol>
2611
2612<h3><a name="General2">General overview</a></h3>
2613
2614<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2615(a file or a remote resource) references another entity. The catalog lookup
2616is inserted between the moment the reference is recognized by the software
2617(XML parser, stylesheet processing, or even images referenced for inclusion
2618in a rendering) and the time where loading that resource is actually
2619started.</p>
2620
2621<p>It is basically used for 3 things:</p>
2622<ul>
2623 <li>mapping from "logical" names, the public identifiers and a more
2624 concrete name usable for download (and URI). For example it can associate
2625 the logical name
2626 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2627 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2628 downloaded</p>
2629 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2630 </li>
2631 <li>remapping from a given URL to another one, like an HTTP indirection
2632 saying that
2633 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2634 <p>should really be looked at</p>
2635 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2636 </li>
2637 <li>providing a local cache mechanism allowing to load the entities
2638 associated to public identifiers or remote resources, this is a really
2639 important feature for any significant deployment of XML or SGML since it
2640 allows to avoid the aleas and delays associated to fetching remote
2641 resources.</li>
2642</ul>
2643
2644<h3><a name="definition">The definitions</a></h3>
2645
2646<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2647<ul>
2648 <li>the older SGML catalogs, the official spec is SGML Open Technical
2649 Resolution TR9401:1997, but is better understood by reading <a
2650 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2651 James Clark. This is relatively old and not the preferred mode of
2652 operation of libxml.</li>
2653 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2654 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2655 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2656</ul>
2657
2658<p></p>
2659
2660<h3><a name="Simple">Using catalog</a></h3>
2661
2662<p>In a normal environment libxml will by default check the presence of a
2663catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2664the processing is completely transparent to the document user. To take a
2665concrete example, suppose you are authoring a DocBook document, this one
2666starts with the following DOCTYPE definition:</p>
2667<pre>&lt;?xml version='1.0'?&gt;
2668&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2669 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2670
2671<p>When validating the document with libxml, the catalog will be
2672automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2673DocBk XML V3.1.4//EN" and the system identifier
2674"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2675been installed on your system and the catalogs actually point to them, libxml
2676will fetch them from the local disk.</p>
2677
2678<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2679DOCTYPE example it's a really old version, but is fine as an example.</p>
2680
2681<p>Libxml will check the catalog each time that it is requested to load an
2682entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2683your system is correctly configured all the authoring phase and processing
2684should use only local files, even if your document stays portable because it
2685uses the canonical public and system ID, referencing the remote document.</p>
2686
2687<h3><a name="Some">Some examples:</a></h3>
2688
2689<p>Here is a couple of fragments from XML Catalogs used in libxml early
2690regression tests in <code>test/catalogs</code> :</p>
2691<pre>&lt;?xml version="1.0"?&gt;
2692&lt;!DOCTYPE catalog PUBLIC
2693 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2694 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2695&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2696 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2697 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2698...</pre>
2699
2700<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2701written in XML, there is a specific namespace for catalog elements
2702"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2703catalog is a <code>public</code> mapping it allows to associate a Public
2704Identifier with an URI.</p>
2705<pre>...
2706 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2707 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2708...</pre>
2709
2710<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2711any URI starting with a given prefix should be looked at another URI
2712constructed by replacing the prefix with an new one. In effect this acts like
2713a cache system for a full area of the Web. In practice it is extremely useful
2714with a file prefix if you have installed a copy of those resources on your
2715local system.</p>
2716<pre>...
2717&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2718 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2719&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2720 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2721&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2722 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2723&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2724 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2725&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2726 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2727...</pre>
2728
2729<p>Delegation is the core features which allows to build a tree of catalogs,
2730easier to maintain than a single catalog, based on Public Identifier, System
2731Identifier or URI prefixes it instructs the catalog software to look up
2732entries in another resource. This feature allow to build hierarchies of
2733catalogs, the set of entries presented should be sufficient to redirect the
2734resolution of all DocBook references to the specific catalog in
2735<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2736references for DocBook 4.2.1 to a specific catalog installed at the same time
2737as the DocBook resources on the local machine.</p>
2738
2739<h3><a name="reference">How to tune catalog usage:</a></h3>
2740
2741<p>The user can change the default catalog behaviour by redirecting queries
2742to its own set of catalogs, this can be done by setting the
2743<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2744empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2745default catalog</p>
2746
2747<h3><a name="validate">How to debug catalog processing:</a></h3>
2748
2749<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2750make libxml output debugging informations for each catalog operations, for
2751example:</p>
2752<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2753warning: failed to load external entity "title.xml"
2754orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2755orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2756Failed to parse catalog /etc/xml/catalog
2757Failed to parse catalog /etc/xml/catalog
2758warning: failed to load external entity "title.xml"
2759Catalogs cleanup
2760orchis:~/XML -&gt; </pre>
2761
2762<p>The test/ent2 references an entity, running the parser from memory makes
2763the base URI unavailable and the the "title.xml" entity cannot be loaded.
2764Setting up the debug environment variable allows to detect that an attempt is
2765made to load the <code>/etc/xml/catalog</code> but since it's not present the
2766resolution fails.</p>
2767
2768<p>But the most advanced way to debug XML catalog processing is to use the
2769<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2770catalogs and make resolution queries to see what is going on. This is also
2771used for the regression tests:</p>
2772<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2773 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2774http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2775orchis:~/XML -&gt; </pre>
2776
2777<p>For debugging what is going on, adding one -v flags increase the verbosity
2778level to indicate the processing done (adding a second flag also indicate
2779what elements are recognized at parsing):</p>
2780<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2781 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2782Parsing catalog test/catalogs/docbook.xml's content
2783Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2784http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2785Catalogs cleanup
2786orchis:~/XML -&gt; </pre>
2787
2788<p>A shell interface is also available to debug and process multiple queries
2789(and for regression tests):</p>
2790<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2791 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2792&gt; help
2793Commands available:
2794public PublicID: make a PUBLIC identifier lookup
2795system SystemID: make a SYSTEM identifier lookup
2796resolve PublicID SystemID: do a full resolver lookup
2797add 'type' 'orig' 'replace' : add an entry
2798del 'values' : remove values
2799dump: print the current catalog state
2800debug: increase the verbosity level
2801quiet: decrease the verbosity level
2802exit: quit the shell
2803&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2804http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2805&gt; quit
2806orchis:~/XML -&gt; </pre>
2807
2808<p>This should be sufficient for most debugging purpose, this was actually
2809used heavily to debug the XML Catalog implementation itself.</p>
2810
2811<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2812
2813<p>Basically XML Catalogs are XML files, you can either use XML tools to
2814manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2815to create a catalog the -create option provide this facility:</p>
2816<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2817&lt;?xml version="1.0"?&gt;
2818&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2819 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2820&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2821orchis:~/XML -&gt; </pre>
2822
2823<p>By default xmlcatalog does not overwrite the original catalog and save the
2824result on the standard output, this can be overridden using the -noout
2825option. The <code>-add</code> command allows to add entries in the
2826catalog:</p>
2827<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2828 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2829 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2830orchis:~/XML -&gt; cat tst.xml
2831&lt;?xml version="1.0"?&gt;
2832&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2833 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2834&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2835&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2836 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2837&lt;/catalog&gt;
2838orchis:~/XML -&gt; </pre>
2839
2840<p>The <code>-add</code> option will always take 3 parameters even if some of
2841the XML Catalog constructs (like nextCatalog) will have only a single
2842argument, just pass a third empty string, it will be ignored.</p>
2843
2844<p>Similarly the <code>-del</code> option remove matching entries from the
2845catalog:</p>
2846<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2847 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2848&lt;?xml version="1.0"?&gt;
2849&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2850 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2851&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2852orchis:~/XML -&gt; </pre>
2853
2854<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2855exact and would have worked in a similar fashion with the Public ID
2856string.</p>
2857
2858<p>This is rudimentary but should be sufficient to manage a not too complex
2859catalog tree of resources.</p>
2860
2861<h3><a name="implemento">The implementor corner quick review of the
2862API:</a></h3>
2863
2864<p>First, and like for every other module of libxml, there is an
2865automatically generated <a href="html/libxml-catalog.html">API page for
2866catalog support</a>.</p>
2867
2868<p>The header for the catalog interfaces should be included as:</p>
2869<pre>#include &lt;libxml/catalog.h&gt;</pre>
2870
2871<p>The API is voluntarily kept very simple. First it is not obvious that
2872applications really need access to it since it is the default behaviour of
2873libxml (Note: it is possible to completely override libxml default catalog by
2874using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2875plug an application specific resolver).</p>
2876
2877<p>Basically libxml support 2 catalog lists:</p>
2878<ul>
2879 <li>the default one, global shared by all the application</li>
2880 <li>a per-document catalog, this one is built if the document uses the
2881 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2882 associated to the parser context and destroyed when the parsing context
2883 is destroyed.</li>
2884</ul>
2885
2886<p>the document one will be used first if it exists.</p>
2887
2888<h4>Initialization routines:</h4>
2889
2890<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2891used at startup to initialize the catalog, if the catalog should be
2892initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2893should be called before xmlInitializeCatalog() which would otherwise do a
2894default initialization first.</p>
2895
2896<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2897own catalog list if needed.</p>
2898
2899<h4>Preferences setup:</h4>
2900
2901<p>The XML Catalog spec requires the possibility to select default
2902preferences between public and system delegation,
2903xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2904xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2905be forbidden, allowed for global catalog, for document catalog or both, the
2906default is to allow both.</p>
2907
2908<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2909(through the xmlGenericError() mechanism).</p>
2910
2911<h4>Querying routines:</h4>
2912
2913<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2914and xmlCatalogResolveURI() are relatively explicit if you read the XML
2915Catalog specification they correspond to section 7 algorithms, they should
2916also work if you have loaded an SGML catalog with a simplified semantic.</p>
2917
2918<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2919operate on the document catalog list</p>
2920
2921<h4>Cleanup and Miscellaneous:</h4>
2922
2923<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2924the per-document equivalent.</p>
2925
2926<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2927first catalog in the global list, and xmlCatalogDump() allows to dump a
2928catalog state, those routines are primarily designed for xmlcatalog, I'm not
2929sure that exposing more complex interfaces (like navigation ones) would be
2930really useful.</p>
2931
2932<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2933it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2934provided because this functionality may be useful for client tools.</p>
2935
2936<h4>threaded environments:</h4>
2937
2938<p>Since the catalog tree is built progressively, some care has been taken to
2939try to avoid troubles in multithreaded environments. The code is now thread
2940safe assuming that the libxml library has been compiled with threads
2941support.</p>
2942
2943<p></p>
2944
2945<h3><a name="Other">Other resources</a></h3>
2946
2947<p>The XML Catalog specification is relatively recent so there isn't much
2948literature to point at:</p>
2949<ul>
2950 <li>You can find an good rant from Norm Walsh about <a
2951 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2952 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame^]2953 I don't agree with everything presented. Norm also wrote a more recent
2954 article <a
2955 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
2956 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2957 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2958 catalog proposal</a> from John Cowan</li>
2959 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2960 Language</a> (RDDL) another catalog system but more oriented toward
2961 providing metadata for XML namespaces.</li>
2962 <li>the page from the OASIS Technical <a
2963 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
2964 Resolution</a> who maintains XML Catalog, you will find pointers to the
2965 specification update, some background and pointers to others tools
2966 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2967 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
2968 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
2969 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
2970 the resources found on the system. Otherwise it will just create
2971 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]2972 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2973 <p>should allow to process DocBook documentations without requiring
2974 network accesses for the DTd or stylesheets</p>
2975 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2976 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2977 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
2978 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2979 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
2980 manual page</a></li>
2981</ul>
2982
2983<p>If you have suggestions for corrections or additions, simply contact
2984me:</p>
2985
2986<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2987
2988<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2989using the XML library from the C language. It is not intended to be
2990extensive. I hope the automatically generated documents will provide the
2991completeness required, but as a separate set of documents. The interfaces of
2992the XML library are by principle low level, there is nearly zero abstraction.
2993Those interested in a higher level API should <a href="#DOM">look at
2994DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]2995
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2996<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
2997separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2998interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2999
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3000<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3001
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3002<p>Usually, the first thing to do is to read an XML input. The parser accepts
3003documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3004defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3005<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3006 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3007 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3008 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3009</dl>
3010<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3011 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3012 <dd><p>Parse an XML document contained in a (possibly compressed)
3013 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3014 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3015</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3016
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3017<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3018failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3019
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3020<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3021
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3022<p>In order for the application to keep the control when the document is
3023being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3024interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3025<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3026 void *user_data,
3027 const char *chunk,
3028 int size,
3029 const char *filename);
3030int xmlParseChunk (xmlParserCtxtPtr ctxt,
3031 const char *chunk,
3032 int size,
3033 int terminate);</pre>
3034
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3035<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3036<pre> FILE *f;
3037
3038 f = fopen(filename, "r");
3039 if (f != NULL) {
3040 int res, size = 1024;
3041 char chars[1024];
3042 xmlParserCtxtPtr ctxt;
3043
3044 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3045 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3046 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3047 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3048 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3049 xmlParseChunk(ctxt, chars, res, 0);
3050 }
3051 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3052 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3053 xmlFreeParserCtxt(ctxt);
3054 }
3055 }</pre>
3056
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3057<p>The HTML parser embedded into libxml also has a push interface; the
3058functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3059
3060<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3061
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3062<p>The tree-building interface makes the parser memory-hungry, first loading
3063the document in memory and then building the tree itself. Reading a document
3064without building the tree is possible using the SAX interfaces (see SAX.h and
3065<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3066Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3067limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3068<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3069
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3070<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3071
3072<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3073there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3074also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3075code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3076<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3077 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3078 xmlNodePtr tree, subtree;
3079
3080 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3081 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3082 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3083 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3084 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3085 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3086 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3087 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3088 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3089 subtree = xmlNewChild(tree, NULL, "image", NULL);
3090 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3091
3092<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3093
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3094<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3095
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3096<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3097code has access to the internal structure of all the elements of the tree.
3098The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3099<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3100<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3101example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3102<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3103
3104<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3105<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3106
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3107<p>points to the text node containing the chapter title "The Linux
3108adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3109
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3110<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3111present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3112to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3113<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3114
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3115<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3116
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3117<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3118is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3119<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3120 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3121 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3122 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3123 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3124 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3125</dl>
3126<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3127 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3128 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3129 <dd><p>This function returns a pointer to new copy of the property
3130 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3131 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3132</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3133
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3134<p>Two functions are provided for reading and writing the text associated
3135with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3136<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3137 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3138 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3139 <dd><p>This function takes an "external" string and converts it to one
3140 text node or possibly to a list of entity and text nodes. All
3141 non-predefined entity references like &amp;Gnome; will be stored
3142 internally as entity nodes, hence the result of the function may not be
3143 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3144 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3145</dl>
3146<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3147 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3148 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3149 <dd><p>This function is the inverse of
3150 <code>xmlStringGetNodeList()</code>. It generates a new string
3151 containing the content of the text and entity nodes. Note the extra
3152 argument inLine. If this argument is set to 1, the function will expand
3153 entity references. For example, instead of returning the &amp;Gnome;
3154 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3155 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3156 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3157</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3158
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3159<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3160
3161<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3162<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3163 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3164 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3165 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3166 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3167</dl>
3168<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3169 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3170 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3171 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3172</dl>
3173<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3174 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3175 <dd><p>Saves the document to a file. In this case, the compression
3176 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3177 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3178</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3179
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3180<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3181
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3182<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3183accesses. The level of compression on saves can be turned on either globally
3184or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3185<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3186 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3187 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3188 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3189</dl>
3190<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3191 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3192 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3193 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3194</dl>
3195<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3196 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3197 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3198 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3199</dl>
3200<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3201 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3202 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3203 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3204</dl>
3205
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3206<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3207
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3208<p>Entities in principle are similar to simple C macros. An entity defines an
3209abbreviation for a given string that you can reuse many times throughout the
3210content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3211may occur frequently within a document, or to confine the change needed to a
3212document to a restricted area in the internal subset of the document (at the
3213beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3214<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32152 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32163 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32174 ]&gt;
32185 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32196 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32207 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3221
3222<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3223its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3224are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3225predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3226<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3227for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3228<strong>&amp;quot;</strong> for the character '"', and
3229<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3230
3231<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3232substitute an entity's content so that you can see the replacement text in
3233your application. Or you may prefer to keep entity references as such in the
3234content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3235precious information (if the user went through the pain of explicitly
3236defining entities, he may have a a rather negative attitude if you blindly
3237susbtitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3238href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3239function allows you to check and change the behaviour, which is to not
3240substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3241
3242<p>Here is the DOM tree built by libxml for the previous document in the
3243default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3244<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3245DOCUMENT
3246version=1.0
3247 ELEMENT EXAMPLE
3248 TEXT
3249 content=
3250 ENTITY_REF
3251 INTERNAL_GENERAL_ENTITY xml
3252 content=Extensible Markup Language
3253 TEXT
3254 content=</pre>
3255
3256<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3257<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3258DOCUMENT
3259version=1.0
3260 ELEMENT EXAMPLE
3261 TEXT
3262 content= Extensible Markup Language</pre>
3263
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3264<p>So, entities or no entities? Basically, it depends on your use case. I
3265suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3266entities in your XML document or data if you are not willing to handle the
3267entity references elements in the DOM tree.</p>
3268
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3269<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3270entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3271transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3272reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3273finding them in the input).</p>
3274
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3275<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3276on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3277non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3278then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3279strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3280deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3281
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3282<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3283
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3284<p>The libxml library implements <a
3285href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
3286recognizing namespace contructs in the input, and does namespace lookup
3287automatically when building the DOM tree. A namespace declaration is
3288associated with an in-memory structure and all elements or attributes within
3289that namespace point to it. Hence testing the namespace is a simple and fast
3290equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3291
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3292<p>I suggest that people using libxml use a namespace, and declare it in the
3293root element of their document as the default namespace. Then they don't need
3294to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3295refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3296the size of the XML output significantly, but significantly increases its
3297value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3298<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3299 &lt;elem1&gt;...&lt;/elem1&gt;
3300 &lt;elem2&gt;...&lt;/elem2&gt;
3301&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3302
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3303<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3304point to any existing resource on the Web. It will bind all the element and
3305atributes with that URL. I suggest to use an URL within a domain you control,
3306and that the URL should contain some kind of version information if possible.
3307For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
3308namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3309
3310<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3311version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3312and if the version information don't match something you know, warn the user
3313and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3314namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3315same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3316associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3317just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3318<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3319prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3320
3321<p>@@Interfaces@@</p>
3322
3323<p>@@Examples@@</p>
3324
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3325<p>Usually people object to using namespaces together with validity checking.
3326I will try to make sure that using namespaces won't break validity checking,
3327so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3328suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3329<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3330flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3331from multiple DTDs will certainly break current validation schemes. I will
3332try to provide ways to do this, but this may not be portable or
3333standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3334
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3335<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3336
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3337<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3338
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3339<p>Version 2 of libxml is the first version introducing serious backward
3340incompatible changes. The main goals were:</p>
3341<ul>
3342 <li>a general cleanup. A number of mistakes inherited from the very early
3343 versions couldn't be changed due to compatibility constraints. Example
3344 the "childs" element in the nodes.</li>
3345 <li>Uniformization of the various nodes, at least for their header and link
3346 parts (doc, parent, children, prev, next), the goal is a simpler
3347 programming model and simplifying the task of the DOM implementors.</li>
3348 <li>better conformances to the XML specification, for example version 1.x
3349 had an heuristic to try to detect ignorable white spaces. As a result the
3350 SAX event generated were ignorableWhitespace() while the spec requires
3351 character() in that case. This also mean that a number of DOM node
3352 containing blank text may populate the DOM tree which were not present
3353 before.</li>
3354</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3355
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3356<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3357
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3358<p>So client code of libxml designed to run with version 1.x may have to be
3359changed to compile against version 2.x of libxml. Here is a list of changes
3360that I have collected, they may not be sufficient, so in case you find other
3361change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3362mail</a>:</p>
3363<ol>
3364 <li>The package name have changed from libxml to libxml2, the library name
3365 is now -lxml2 . There is a new xml2-config script which should be used to
3366 select the right parameters libxml2</li>
3367 <li>Node <strong>childs</strong> field has been renamed
3368 <strong>children</strong> so s/childs/children/g should be applied
3369 (probablility of having "childs" anywere else is close to 0+</li>
3370 <li>The document don't have anymore a <strong>root</strong> element it has
3371 been replaced by <strong>children</strong> and usually you will get a
3372 list of element here. For example a Dtd element for the internal subset
3373 and it's declaration may be found in that list, as well as processing
3374 instructions or comments found before or after the document root element.
3375 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
3376 a document. Alternatively if you are sure to not reference Dtds nor have
3377 PIs or comments before or after the root element
3378 s/-&gt;root/-&gt;children/g will probably do it.</li>
3379 <li>The white space issue, this one is more complex, unless special case of
3380 validating parsing, the line breaks and spaces usually used for indenting
3381 and formatting the document content becomes significant. So they are
3382 reported by SAX and if your using the DOM tree, corresponding nodes are
3383 generated. Too approach can be taken:
3384 <ol>
3385 <li>lazy one, use the compatibility call
3386 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3387 relying on a special (and possibly broken) set of heuristics of
3388 libxml to detect ignorable blanks. Don't complain if it breaks or
3389 make your application not 100% clean w.r.t. to it's input.</li>
3390 <li>the Right Way: change you code to accept possibly unsignificant
3391 blanks characters, or have your tree populated with weird blank text
3392 nodes. You can spot them using the comodity function
3393 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3394 nodes.</li>
3395 </ol>
3396 <p>Note also that with the new default the output functions don't add any
3397 extra indentation when saving a tree in order to be able to round trip
3398 (read and save) without inflating the document with extra formatting
3399 chars.</p>
3400 </li>
3401 <li>The include path has changed to $prefix/libxml/ and the includes
3402 themselves uses this new prefix in includes instructions... If you are
3403 using (as expected) the
3404 <pre>xml2-config --cflags</pre>
3405 <p>output to generate you compile commands this will probably work out of
3406 the box</p>
3407 </li>
3408 <li>xmlDetectCharEncoding takes an extra argument indicating the lenght in
3409 byte of the head of the document available for character detection.</li>
3410</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3411
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3412<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3413
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3414<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
3415to allow smoth upgrade of existing libxml v1code while retaining
3416compatibility. They offers the following:</p>
3417<ol>
3418 <li>similar include naming, one should use
3419 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3420 <li>similar identifiers defined via macros for the child and root fields:
3421 respectively <strong>xmlChildrenNode</strong> and
3422 <strong>xmlRootNode</strong></li>
3423 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3424 inserted once in the client code</li>
3425</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3426
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3427<p>So the roadmap to upgrade your existing libxml applications is the
3428following:</p>
3429<ol>
3430 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
3431 <li>find all occurences where the xmlDoc <strong>root</strong> field is
3432 used and change it to <strong>xmlRootNode</strong></li>
3433 <li>similary find all occurences where the xmlNode <strong>childs</strong>
3434 field is used and change it to <strong>xmlChildrenNode</strong></li>
3435 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3436 <strong>main()</strong> or in the library init entry point</li>
3437 <li>Recompile, check compatibility, it should still work</li>
3438 <li>Change your configure script to look first for xml2-config and fallback
3439 using xml-config . Use the --cflags and --libs ouptut of the command as
3440 the Include and Linking parameters needed to use libxml.</li>
3441 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3442 libxml-devel-1.8.y can be kept simultaneously)</li>
3443 <li>remove your config.cache, relaunch your configuration mechanism, and
3444 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3445 <li>Test that your application is still running correctly, if not this may
3446 be due to extra empty nodes due to formating spaces being kept in libxml2
3447 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3448 code before calling the parser (next to
3449 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3450</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3451
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3452<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3453
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3454<p>Let me put some emphasis on the fact that there is far more changes from
3455libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3456has been considerably cleaned up and the conformance to the XML specification
3457has been drastically improved too. Don't take those changes as an excuse to
3458not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3459
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3460<h2><a name="Thread">Thread safety</a></h2>
3461
3462<p>Starting with 2.4.7, libxml makes provisions to ensure that concurent
3463threads can safely work in parallel parsing different documents. There is
3464however a couple of things to do to ensure it:</p>
3465<ul>
3466 <li>configure the library accordingly using the --with-threads options</li>
3467 <li>call xmlInitParser() in the "main" thread before using any of the
3468 libxml API (except possibly selecting a different memory allocator)</li>
3469</ul>
3470
3471<p>Note that the thread safety cannot be ensured for multiple threads sharing
3472the same document, the locking must be done at the application level, libxml
3473exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3474The parts of the library checked for thread safety are:</p>
3475<ul>
3476 <li>concurrent loading</li>
3477 <li>file access resolution</li>
3478 <li>catalog access</li>
3479 <li>catalog building</li>
3480 <li>entities lookup/accesses</li>
3481 <li>validation</li>
3482 <li>global variables per-thread override</li>
3483 <li>memory handling</li>
3484</ul>
3485
3486<p>XPath is supposed to be thread safe now, but this wasn't tested
3487seriously.</p>
3488
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3489<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3490
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3491<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3492Object Model</em>; this is an API for accessing XML or HTML structured
3493documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3494and will be based on gnome-xml. This will be a far cleaner interface to
3495manipulate XML files within Gnome since it won't expose the internal
3496structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3497
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3498<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3499href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3500is a full DOM interface, thanks to Paolo Casarini, check the <a
3501href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3502informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3503
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3504<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3505
3506<p>Here is a real size example, where the actual content of the application
3507data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3508a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3509storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3510base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3511<pre>&lt;?xml version="1.0"?&gt;
3512&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3513 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3514
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3515 &lt;gjob:Job&gt;
3516 &lt;gjob:Project ID="3"/&gt;
3517 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3518 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3519
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3520 &lt;gjob:Update&gt;
3521 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3522 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3523 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3524 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3525
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3526 &lt;gjob:Developers&gt;
3527 &lt;gjob:Developer&gt;
3528 &lt;/gjob:Developer&gt;
3529 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3530
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3531 &lt;gjob:Contact&gt;
3532 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3533 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3534 &lt;gjob:Company&gt;
3535 &lt;/gjob:Company&gt;
3536 &lt;gjob:Organisation&gt;
3537 &lt;/gjob:Organisation&gt;
3538 &lt;gjob:Webpage&gt;
3539 &lt;/gjob:Webpage&gt;
3540 &lt;gjob:Snailmail&gt;
3541 &lt;/gjob:Snailmail&gt;
3542 &lt;gjob:Phone&gt;
3543 &lt;/gjob:Phone&gt;
3544 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3545
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3546 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3547 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3548 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3549
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3550 &lt;gjob:Skills&gt;
3551 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3552
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3553 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3554 A GNOME based system that will allow a superuser to configure
3555 compressed and uncompressed files and/or file systems to be backed
3556 up with a supported media in the system. This should be able to
3557 perform via find commands generating a list of files that are passed
3558 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3559 or via operations performed on the filesystem itself. Email
3560 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3561 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3562
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3563 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3564
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3565 &lt;/gjob:Jobs&gt;
3566&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3567
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3568<p>While loading the XML file into an internal DOM tree is a matter of
3569calling only a couple of functions, browsing the tree to gather the ata and
3570generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3571
3572<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3573structure. For example, the ordering of the attributes is not significant,
3574the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3575depend on the order of the children of a given node, unless it really makes
3576things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3577<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3578 * A person record
3579 */
3580typedef struct person {
3581 char *name;
3582 char *email;
3583 char *company;
3584 char *organisation;
3585 char *smail;
3586 char *webPage;
3587 char *phone;
3588} person, *personPtr;
3589
3590/*
3591 * And the code needed to parse it
3592 */
3593personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3594 personPtr ret = NULL;
3595
3596DEBUG("parsePerson\n");
3597 /*
3598 * allocate the struct
3599 */
3600 ret = (personPtr) malloc(sizeof(person));
3601 if (ret == NULL) {
3602 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3603 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3604 }
3605 memset(ret, 0, sizeof(person));
3606
3607 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3608 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3609 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3610 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3611 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3612 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3613 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3614 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3615 }
3616
3617 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3618}</pre>
3619
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3620<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3621<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3622 <li>Usually a recursive parsing style is the more convenient one: XML data
3623 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3624 stuctured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3625 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3626 i.e. the pointer to the global XML document and the namespace reserved to
3627 the application. Document wide information are needed for example to
3628 decode entities and it's a good coding practice to define a namespace for
3629 your application set of data and test that the element and attributes
3630 you're analyzing actually pertains to your application space. This is
3631 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3632 <li>To retrieve text and attributes value, you can use the function
3633 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3634 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3635</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3636
3637<p>Here is another piece of code used to parse another level of the
3638structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3639<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3640/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3641 * a Description for a Job
3642 */
3643typedef struct job {
3644 char *projectID;
3645 char *application;
3646 char *category;
3647 personPtr contact;
3648 int nbDevelopers;
3649 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3650} job, *jobPtr;
3651
3652/*
3653 * And the code needed to parse it
3654 */
3655jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3656 jobPtr ret = NULL;
3657
3658DEBUG("parseJob\n");
3659 /*
3660 * allocate the struct
3661 */
3662 ret = (jobPtr) malloc(sizeof(job));
3663 if (ret == NULL) {
3664 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3665 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3666 }
3667 memset(ret, 0, sizeof(job));
3668
3669 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3670 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3671 while (cur != NULL) {
3672
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3673 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3674 ret-&gt;projectID = xmlGetProp(cur, "ID");
3675 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3676 fprintf(stderr, "Project has no ID\n");
3677 }
3678 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3679 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3680 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3681 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3682 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3683 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3684 ret-&gt;contact = parsePerson(doc, ns, cur);
3685 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3686 }
3687
3688 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3689}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3690
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3691<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3692boring. Ultimately, it could be possble to write stubbers taking either C
3693data structure definitions, a set of XML examples or an XML DTD and produce
3694the code needed to import and export the content between C data and XML
3695storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3696
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3697<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3698parsing example</a> as a template, it is also available with Makefile in the
3699Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3700
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3701<h2><a name="Contributi">Contributions</a></h2>
3702<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3703 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3704 patches, Gary Pennington worked on the validation API, threading support
3705 and Solaris port.</li>
3706 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3707 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
3708 for libxml:<br>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]3709 Website: <a
3710 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
3711 Download: <a
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]3712 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3713 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3714 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3715 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3716 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3717 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3718 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3719 <li><a
3720 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3721 Sergeant</a> developped <a
3722 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
3723 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3724 application server</a></li>
3725 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3726 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3727 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3728 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3729 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3730 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3731 <li>there is a module for <a
3732 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3733 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3734 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3735 first version of libxml/libxslt <a
3736 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3737 <li>Petr Kozelka provides <a
3738 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3739 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3740 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3741 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3742 Digital Signature</a> <a
3743 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3744</ul>
3745
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3746<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3747</body>
3748</html>